The revised American Society for Reproductive Medicine (rASRM) score is currently the best-known classification of endometriosis and is the one most widely used throughout the world. It is relatively easy to use, but it does not take into account the involvement of retroperitoneal structures with deeply infiltrating endometriosis. For this reason, the Enzian classification was developed as a supplement to the rASRM score, in order to provide a morphologically descriptive classification of deeply infiltrating endometriosis. The Enzian classification currently has a poor level of international acceptance and is mainly used in the German-speaking countries. It was revised in 2011 and is now also easier to use. This article describes the strengths and weaknesses of the rASRM score and the Enzian classification and their common potential for classifying endometriosis.