The Cooperative Patent Classification (CPC), is developed by a joint partnership between the USPTO and the EPO. CPC would be used EPO and USPTO from Jan. 1, 2013, replacing ECLA and USPTO classifications. The CPC is a hierarchical numeric classification scheme in the format which is WIPO ST.8 Standard (IPC)-compliant. CPC is mostly based on ECLA, and includes all ECLA groups, all EPO ICOs and vast majority of EPO "keywords (KW), and extended by USCL Class 701 "Business Methods" and USPC cross-reference art collections (XRACs) and digests (with a space left for possibility of JPO F/FI codes inclusion).  A Complete CPC Scheme (625 CPC classes) was published in Oct.2012 .pdf format (and also available in .xml format ). CPC class definitions has been adding in batches (88 of 625, as of Nov. 6, 2012), and it is anticipated that all batches will be completed by early 2013. Espacenet would be a public browser of CPC (instead of ECLA), from December 2012). A CPC learning module is provided by the EPO Academy. See CPC News for further updates.

DWPI Classification homepage - Official site for the classification scheme used by Thompson Derwent to classify documents on the World Patent Index

ECLA Classification homepage - Schedules and indexes to the European patent classification within the Espacenet patent database, allowing direct pasting into advanced search form

International Patent Classification Compilation of Amendments to the 7th edition - Word document

International Patent Classification e-Forum - View current projects and discussion documents for proposed IPC changes

International Patent Classification File Download Area - Previous and current IPC editions in full in various file formats

International Patent Classification Home Page - Official WIPO homepage for all IPC material

International Patent Classification Schedules - Schedules for the current IPC and all previous editions from IPC1 to date

Japanese F-Term Patent Map Guidance - Schedules of Japanese F-Term classification with concordance between F-Terms and IPC

UK Patent Classification - Schedules, index and IPC concordance for the former United Kingdom Patent Office Classification (no longer used but may appear on old documents)

US Classification official website - Official USPTO web page for US classification, with links to classification schedules, indexes, and concordances to International Patent Classification Eighth Edition and Locarno Classification for registered designs

US Classification concordance from Standard Industry Code - Concordance from the classification system commonly used for business areas in the business information world to the US patent classification