CATALOGING POLICY AND SUPPORT OFFICE

LCCN RESTRUCTURING TO FOUR-DIGIT YEAR

The Library of Congress Control Number (LCCN) is being restructured to allow the year portion to be represented by four digits. This change, applicable both to bibliographic and authority records, will make it possible to distinguish clearly the century in which a particular LCCN was assigned (not possible if a year is represented by only the last two digits of the year). Under the four-digit year LCCN, the overall length of the LCCN remains at 12 positions, but data constituting the LCCN have been shifted such that

  1. the positions allocated to prefixes have been reduced from three to two;
  2. the positions allocated to year have been expanded from two to four;
  3. there is no longer a "trailing blank" at the end of the number.

The change will be implemented January 2, 2001.

The attached DCM C3 provides background information on the LCCN, describes in detail the old structure (two-digit year) and the new structure (four-digit year), and provides instructions on applying the new LCCN structure. Since records containing the old LCCN structure are not being changed, it is possible to have a mixture of numbers in field 010 (Library of Congress Control Number). Instructions are also included that address this condition.

Select this link for text of DCM C3

(This is a PDF file that requires the Adobe Acrobat Reader, available for free download by selecting this link.)

Go to:

Library of Congress

Library of Congress Help Desk (12/08/2000)