This SAE Standard outlines the engine oil performance categories and classifications developed through the efforts of the Alliance of Automobile Manufacturers (AAM), American Petroleum Institute (API), the American Society for Testing and Materials (ASTM), the Engine Manufacturers Association (EMA), International Lubricant Standardization and Approval committee (ILSAC) and SAE. The descriptions by API and ASTM, along with prescribed test methods and limits are shown for active categories in Table 1 and obsolete categories in Table A1. Appendix A is a historical documentation of the obsolete categories. For purposes of this document, active categories are defined as those (a) for which the required test equipment and test support materials, including reference engine oils and reference fuels, are readily available, (b) for which ASTM or the test developer monitors precision for all tests, and (c) which are currently available for licensing by API EOLCS. The current processes for initiating new classifications were developed through the cooperative efforts of the AAM, API, ASTM, EMA, ILSAC, and SAE. New API “S” and ILSAC classifications are added using the procedure defined in API 1509 Appendix C. New API “C” categories are developed through agreement among EMA, API, and ASTM.