The European Patent Office (EPO) and the United States Patent and Trademark Office (USPTO) have launched a global classification system for patent documents called the Cooperative Patent Classification scheme (CPC). The CPC has been developed to harmonise the patent granting processes of the two offices.


In recent years, the rise in the number of patent applications cross-filed in intellectual property offices around the world has generated significant interest in patent examiner work-sharing. Since October 2010, the EPO and the USPTO have worked together to develop the CPC, with the goal of developing and implementing a common classification system that will be compatible with other major intellectual property offices. The CPC is built on the foundation of the European Patent Classification system (ECLA) - utilising the same hierarchy, titles and expandability functions - however, it also incorporates a few entries from the United States Patent Classification system (USPC). Like the ECLA, the CPC is based on the International Patent Classification system so it can be cross-referenced with international patent libraries.

The EPO and the USPTO both have their own sophisticated patent classification systems. The CPC is intended to combine the best practices from each of these offices, with the move to a jointly maintained classification system designed to:

  • enhance efficiency by reducing duplication of work. This will allow users to refer to one system, rather than having to use both to achieve maximum document retrieval, which should result in time and cost savings;
  • improve navigation and understanding of patent classifications by removing the complexity introduced by multiple classification systems;
  • facilitate work-sharing on patent applications filed in multiple intellectual property offices. USPTO and EPO examiners will be able to collaborate and exchange classification and search ideas by referring to and using work completed by other intellectual property offices; and
  • improve the consistency of search results across intellectual property offices.


The CPC was launched officially on 2 January 2013. After its entry into force, the ECLA ceased to exist and the EPO now classifies all documentation using the CPC. The same is not true of the USPTO, which is subject to a transition period until the end of 2014. During this time, newly filed US applications will be classified in USPC and CPC, while all other publications will be classified either in USPC, or in USPC and CPC. In the short term, this will result in an increased classification burden, as a thorough search will require searching all existing class systems. From the start of 2015, the USPTO will join the EPO in classifying documents exclusively in CPC (except for documents relating to plants and designs).

The CPC will remain unchanged for an initial period of three months. The first CPC revisions will take place as of April 2013 in mutual agreement between the EPO and the USPTO. After this time, the offices will work together on regular revisions designed to allow for a rapid response to new technological developments or filing trends. As collaborative revisions must be approved by both the EPO and USPTO, this process may not be as responsive as desired if either of the offices is unable to make these revisions a top priority. At any rate, the CPC will deviate increasingly from its launch version, and thus from the ECLA.


As a global system, the CPC can now be used by more than 45 patent offices, allowing patent examiners and patent system users alike to conduct document searches of the same document collections. The realisation of the aims of the CPC will hinge on the effectiveness of examiner retraining, the quality of re-classification of existing patent documents, the responsiveness of the offices in implementing adaptive updates to the system and the level of uptake by other intellectual property offices around the world.