First indicator - Existence in LC collection

#  No information provided

0  Item is in LC

1  Item is not in LC

Second indicator - Source of class/call number

0  Assigned by LC

4  Assigned by agency other than LC  [i.e., CONSER member]


a  Class number (R)

b  Item number (NR)

u  Custody, permanent (R)  [Obsolete]

3  Materials specified (NR)

6  Linkage (NR)

8  Field link and sequence number (R)

NOTE:  See MARC 21 Format for Bibliographic Data (050 Library of Congress Call Number) for code definitions not given below.


Field 050 contains an LC call number, shelf number, or pseudo-call number.  This field is an authoritative agency field.  The Library of Congress, the authoritative agency, maintains the Library of Congress Classification Schedules, which are kept up-to-date by LC ClassificationAdditions and Corrections.  When an LC class number is assigned by a CONSER member other than LC, it must be based on these sources.

Field 090 contains an LC class number assigned by a non-CONSER institution.

Repeatability and order of input

Field 050 is repeatable in the following instances:

a.   When some issues of a serial have been issued in one or more collected series during the history of the serial's publication.  Each call number is given in a separate 050 field.  The current call number is always given first; earlier call numbers are given in chronological sequence.  Each call number for a collected series is also recorded in the 490 field for the series title.

b.   When a CONSER member assigns a true class/call number to a record that has only a non-classification LC call number or retention decision.

c.   When a CONSER member assigns a true class/call number to a record already containing a full classification number assigned by LC because (1) the existing 050 no longer reflects usage of the most current class schedules/Additions and Changes or (2) an alternative class number is needed for classing:  a) a bibliography with the subject rather than class Z, b) fiction in a literature number rather than class PZ, or c) a subseries classed separately from a collected main series.

d.   When a CONSER member inputs or performs maintenance on a non-LC-authenticated record involving situations covered in a, b, and c above.

e.   When LC discovers errors that led to a single serial having two or more call numbers, both of which are valid in LC's shelf list and volume labels.

050 00 HN281 $b .C33 $3 Applies to: no. 131-

050 00 HN281 $b .C45a $3 Applies to: no. 29-130

f.   When a legitimate classification number for the subject, at either the analytic or series level, is given in field 050 14 and it is different from the classification number assigned by LC.

[NOTE:  A separate 050 field is never input by a CONSER member merely to record a local cutter that differs from that of a full call number already present in a record.  When LC adds a full call number to a record already containing one input by another CONSER member, LC will overlay any existing 050 field, with the exceptions noted above.  Only the classification portion of the number need match to be considered eligible for deletion.]

LC-assigned call numbers should precede call number assigned by other agencies.

First indicator - Existence in LC collection

The first indicator identifies the presence of the serial in LC under the call number given.  The values are defined and used as follows:

#    No information provided.

Used by agencies other than LC when inputting field 050 to original or non-LC cataloging records, and it is not known if the item is in LC.  This value is used only in conjunction with second indicator value "4," although it may appear as a default value on some older OCLC records.

050 #4 S494.A2 $b J7

050 #4 DT751.S64 $b A4

0    Item is in LC.

Used to indicate that the item is in LC under the call number given in the field.  Agencies should use this value when transcribing LC cataloging copy, unless the call number is bracketed or preceded by a Maltese cross (see instructions below).  This value is used only in conjunction with second indicator value "0".

050 00 PA11 $b .C7

050 00 KFC1177.A29 $b C34

1    Item is not in LC.

Used to indicate that an item is not held by LC or is not in LC under the call number assigned.  This value is used in the following situations:

a.   When the call number has been bracketed in the LC Official Catalog or Shelflist (indicating withdrawal), or when transcribing LC copy on which the call number appears in brackets or is preceded by a Maltese cross.

050 10 Z1007 $b .B57

b.   When the words "NOT IN LC" are input in field 050 (see explanation under section on Pseudo call numbers).

050 10 NOT IN LC

c.   When a CONSER member assigns a call number to a serial that is known to be "not in LC."

[NOTE:  CONSER members should assume a serial is "not in LC" if the serial began publication 1981 or later, and there is no LC-authenticated record in OCLC.]

050 14 RC970 $b .M34

[Began 1985; no LC-authenticated record on OCLC.]

d.   When a CONSER member assigns a class/call number to an LC-authenticated record that has a LC call number.


050 14 QE515 $b .M4

050 00 WMLC L 83/666

050 14 HG3425.A8 $b B3

050 00 Microfilm 05422

050 14 BX801 $b .C35

050 00 Z3658.A8 $b E37

050 14 DT56.9 $b .E37

050 00 LAW

050 14 KF412 $b .H43


050 14 AP2 $b .D74

050 00 DISCARD

050 14 SF383 $b .G25

050 00 PZ1.A1 $b N35

050 14 PS648.S3 $b N35

[NOTE:  When LC adds a classification call number to a record with a call number assigned by another member that has a first indicator value of blank, LC will change the blank to "1".]

e.   When a CONSER member creates a record for a monographic series that the series authority record indicates is analyzes and classed separately by LC.  CONSER members may add an 050 field with "classed separately" to indicated that LC has assigned separate classification numbers to individual mongraphs.


050 14 QE515 $b .M4

f.    When a CONSER member creates a record for a major change (including record separations, as described in C8.3) and carries the LC-assigned call number over to the new record.  The indicator values are "14" in such a case.  If LC claims the record later, the indicator values will be changed to "00".

Second indicator - Source of class/call number

The second indicator specifies the source of classification or call number assignment.  Indicator values are defined and used as follows:

#    No information provided.  [Obsolete]

This indicator is not used under current practice but will appear as a default value on older records.

0    Assigned by LC.

Used to indicate that the class/call number has been assigned by the Library of Congress.  It is used by other agencies when transcribing call numbers from LC cataloging copy, but not when creating a record for a major change and carrying the LC-assigned call number over to the new record.  (Second indicator "4" is used then.)

050 00 JK609 $b .M2

[Call no. assigned and input by LC.]

050 00 QK232 $b .M3

[Call no. input by other agency from LC cataloging copy.]

4    Assigned by agency other than LC.  [i.e., CONSER member]

Used when assigning a class/call number derived from the LC classification schedules, including when a CONSER member creates a record for a major change and carries the LC-assigned call number over to the new record.  Only one 050 field with this indicator value should be input in a record.  LC will change indicator 4 to 0 if it subsequently uses a call number input by another institution.

050 14 GF1 $b .O67

050 #4 HG4057 $b .A42


$a  Class number.

Subfield $a contains the class number (that part of the number pertaining to the subject of the serial as assigned from the LC schedules).  The class number includes all letters, numbers, and spaces preceding the last capital letter (or the period preceding it).

050 00 HF5314.V52 $b U54

050 00 ML5 $b .E5683

050 00 JX1974.7 $b .M5

050 00 KF112 7th.1 $b .S48

When the call number consists only of a class number (i.e., the number consists solely of letters followed by numbers, possibly including a period), the entire number is included in subfield $a.

050 00 HF5415.13

050 00 JK4531

Alternative class numbers (such as those printed on LC cards following the LC call number and enclosed in brackets) are input in a subsequent subfield $a following the full call number.  The brackets are not input.

050 00 HD8051 $b .A62 subser. $a HD4966.C45

Other forms of call numbers (e.g., LAW, CLASSED SEPARATELY) are also input as subfield $a.  For further information see explanation under section on Pseudo call numbers.

$b  Item number.

Subfield $b contains the part of the number pertaining to the individual piece plus dates or words that follow the class/call number.  The delimiter and subfield code "b" precede the last capital letter in the call number or the period preceding it.

050 00 Z673.L7 $b Y

050 00 HF5314.V52 $b U54

050 00 JX1974.7 $b .M5

050 00 PZ7.K23 $b Dan

If the class number is followed only by a date (i.e., no Cutter number), input the date in subfield $b.  A date is always preceded by one space when it occurs as the first item in subfield $b.  Dates and volume numbers occurring within a subfield should be preceded by one space.

050 00 JS1222 $b 1967

050 00 G108 $b .A289 1959

050 00 VM341 $b .M9 vol. 48

050 00 DK274.3 1968 $b .K39

050 00 J87 $b .M4 date p

The terms "subser." and "Suppl." are separated from the item number by one space.  If there is no item number code, still input the term in subfield $b.  The term "Suppl." is always capitalized; "subser." is not capitalized.

050 00 HA1173 $b .A27 subser.

050 00 Z1223 $b .C75 Suppl.

050 00 HA1631 $b subser.

050 00 HA1538 $b Suppl.

$u  Custody, permanent (LC use).  [Obsolete]

LC input its local custody information in subfield $u, including reference assignments, special collections identification, and shelf locations.  This information is no longer recorded in CONSER records but existing data remains in OCLC records.

050 00 AP95.K6 $b S48 $u <Orien Korea>

050 00 LAW $u <US 8 LABOR>

050 00 PG1203.V8 $b Z33 $u <fol.>

Approved office symbols were input in angle brackets following the call number.

050 00 HE5623 $b .A25 $u <MRR Alc>

050 00 Z6004 $b .H9 $u <SciRR>

Subfield $u was sometimes repeated for shelf locations and custody assignments.

050 00 TA368 $u <1996 00964> $u MRC>

Subfield $u was also used for custodial areas or collections to which unchecked material was distributed when a title was not fully cataloged.

050 00 UNCLASSED $u <Asian>

$3  Materials specified.

Subfield $3 contains information that indicates the part of the described material to which the field applies.  Its use is parallel with the use of subfield $3 in other fields.

$6  Linkage.

For instructions on the use of subfield $6, see field 880.

Pseudo call numbers (FN 1) and other forms of LC call numbers

The following call numbers are used by LC for various types of serials or to describe the status of the serial at the time of input.

LAW.  The term "LAW" (for law materials for which there is/was no "K" class available at time of cataloging) is input as subfield $a in all uppercase letters.

050 00 $a LAW

Newspaper.  The term "Newspaper" is input in subfield $a with the first letter capitalized.

050 00 $a Newspaper

The presence of this word indicates that the item is considered a newspaper within LC.  Some newspaper call numbers include a control number.  In such cases, subfield $a contains the term "Newspaper" and the control number.

050 00 $a Newspaper 7225-X

ISSN RECORD.  Input by staff of the National Serials Data Program (NSDP) for the purpose of bringing records created in association with ISSN assignments into the LC database.  It is used under the following two conditions:  1) a decision has been made not to acquire the title for the Library of Congress collections or 2) no acquisitions decision has yet been made (usually because the title is still in the prepublication stage or because publisher did not submit a full issue when requesting an ISSN).  If a title being assigned an ISSN is also being acquired by LC, normal 050 values are used.  If the title is later acquired and cataloged for LC's collections, the 050 01 ISSN RECORD will be replaced by the LC class number or other appropriate 050 information.

050 10 $a ISSN Record

IN PROCESS (LC use).  This phrase, given in all uppercase letters, denotes a record for which the descriptive cataloging has been completed in LC, but that has yet to be assigned subject headings and classification/call numbers.  Such records include encoding level "5" and the first indicator in field 050 is always set to "0."

ENC LVL (Leader/17):  5

042 ## $a lc

050 00 $a IN PROCESS

If an LC cataloger has a partial class number before shelflisting is completed, it is sometimes given in brackets with a plus sign and may be preceded by the words IN PROCESS:

ENC LVL (Leader/17):  5

042 ## $a lc

050 00 $a IN PROCESS [F123+]

Prior to 1990, LC catalogers used "PAR" to indicate that the record was a "partial" record, i.e., one without subject headings.  If major changes in description or in access points were made to partial records by LC before they were upgraded to full level cataloging, the pseudo call number was changed by LC to "REV PAR" (revised partial).  Beginning in 1990, LC catalogers use "IN PROCESS" rather than "PAR"; no further notation is used to indicate changes.

After the subject elements are assigned, the information is added to the online record and the record is upgraded to a full or core level record, (i.e., the encoding level is changed to "#" or "4").  The increase in encoding level will cause the OCLC system to automatically set the record status (Leader/05) to "a".

ENC LVL (Leader/17):  #

REC STAT (Leader/05):  a

042 ## $a lc

050 00 $a 00HV1 $b .M63

CLASSED SEPARATELY.  Beginning in 1990, the uppercase words "CLASSED SEPARATELY" are used when LC holds a serial that is a monographic series that is classed separately in LC.  These records carry an "sf"-prefixed LC card number prior to May 1999, and the first indicator in field 050 is always set to "0".

SER TP (008/21):  m

010 ## $a sf90-10042


Prior to 1990, the uppercase letters "UNC" were used to indicate a monographic series classed separately in LC (see below).

UNCLASSED.  The uppercase words "UNCLASSED" appearing in LC minimal-level records indicates that LC holds a serial, but no classification number has been assigned.  In some instances the word is accompanied by an item number.

050 00 $a UNCLASSED

050 00 $a UNCLASSED $b S-100

UNC.  The three uppercase letters "UNC" (UNCataloged or UNClassified) appearing in older LC records indicates that LC holds a serial, but  no call number was assigned.  Items that fell into this category include:  form card cataloging, temporary cataloging, and monographic series classed separately.  [NOTE:  Current practice for handling items in these categories is to assign a call number to serials that are collected, or to use "CLASSED SEPARATELY" or "UNCLASSED."]

NOT IN LC.  The uppercase words "NOT IN LC" are input when transcribing data from LC cooperative cataloging copy and no LC call number is present.  The first indicator in the 050 field should always be set to "1".  A regular LCCN should always be present.

010 ## $a gs46-155

050 10 $a NOT IN LC

Microform call numbers

a.   New system (1982- ).  The microform call number consists of:

1.   a designation of the type of microform (e.g., Microfiche);

2.   one of the following letters enclosed in parentheses:

(o) open entry

(w) requires special filing consideration

Omission of this element indicates that the microform is complete.

3.   the control number;

050 00 Microfilm (o) 82/528

050 00 Microfilm (w) 82/14206

050 00 Microfiche 82/302

b.   Old system (pre-1982).  Prior to 1982, microform call numbers consisted of the designation of microform (e.g., Microfilm) followed by the control number.  In the case of fiche, the control number may actually be an LC class number.  In the case of film, the control number is sometimes followed by a space and one or more letters of an LC class.

050 00 Microfiche D839.3

050 00 Microfilm 05030 PC

Retention decisions

When LC authenticates a CONSER member record for a serial that is not permanently retained in LC, LC's retention decision is input in this field.  Some LC minimal level records, cataloged during an experimental period, also carry an indication of LC's retention decision.

050 10 DISCARD


If LC creates a separate CURRENT ISSUES ONLY record for an item that is cumulated or replaced by a permanent edition (e.g., advance sheets that are replaced by cumulative law reports), the call number of the permanent edition is input in a subsequent subfield $a.


Shelf numbers

Minimal level records for printed materials retained in LC's permanent collection carry a shelf number.  The shelf number consists of:

1.   the capital letters "WMLC";

2.   the letter L (large, for numbers beginning with 82/ or 83/), or F (folio)

3.   the control number.

050 00 WMLC L 82/1234

050 00 WMLC F 82/976

050 00 WMLC 90/7878

Some nonprint materials in LC's collection do not receive a class number, only a shelf number.

050 00 RYB 8778-

Beginning in 1998, minimal level shelf numbers for serials in the custody of the Asian Division and the African and Middle Eastern Division adopted the system used for minimal level monographs in those divisions.  The shelf number consists of "WMLC" followed by a letter for size (S = small; M = medium; L = large; F = folio), followed by a letter representing the custodial assignment (e.g., A = South Asia material in Asian Division; N = Near East Section, African and Middle Eastern Division).

050 00 WMLCSA  98/00006

[small size item, South Asia materials]

050 00 WMLCMN  98/00015

[medium size item, Near East Section]

Libraries are free to change LC call numbers in their local systems, especially if it is a matter of local preference or cataloger's judgment.  When doing so, it is recommended to change the second indicator value to "4."  LC/PSD would be receptive to reports about erroneous call numbers only.  If the class number was correct when it was originally assigned, LC/PSD general policy is not to reclass.

Related fields, etc.

051, 440, 490, 901

050 Library of Congress Call Number  (MARC 21 Format for Bibliographic Data)

See also:

01X-09X  Numbers and Codes

Variable Data Fields

Section E.  MARC 21 Format for Serials as Applied Within CONSER

CONSER Editing Guide:  Contents