Endometriosis associated pain (EAP) has a significant impact on the quality of life of those affected and their families. Recognizing that endometriosis is a chronic condition associated with an impairment in function and negative social impact, there is a shift towards reducing diagnostic delays and initiating timely management. This article provides a comprehensive and practical approach to the clinical diagnosis of EAP, which can subsequently facilitate prompt and directed treatment. The key components of the history, physical exam and high-quality imaging to evaluate suspected EAP and related pain conditions are presented. Currently, biomarkers have limited utility in the diagnosis of endometriosis, but research in this area continues; development of a reliable non-invasive test for endometriosis may further improve early identification of this condition.