BACKGROUND AND OBJECTIVE: Laparoscopy is the standard method to visually identify endometriotic lesions under magnification within and outside the minor pelvis. The aim of this study was to analyze the accuracy of laparoscopic visualization in diagnosing the various endometriotic sites as confirmed histologically. METHOD: Presumed endometriotic sites were observed in 164 patients operated on under the clinical suspicion of endometriosis. Targeted biopsies were performed for histologic corroboration, comparing the laparoscopic findings and diagnosis to the histological results. RESULT: The histological reports of the biopsies confirmed the presence of endometriosis in 138 patients (84.1%), but in 26 patients (15.9%), no evidence of endometriosis was observed. 100% of "red" lesions, 92% of "black" lesions, and 31% of "white" lesions turned out to be endometriosis. Of the 264 various suspected endometriotic sites observed, 142 (53.8%) were confirmed histologically. The most accurate diagnosis was in lesions on the parietal peritoneum of the pelvis, confirmed in 9/9 cases (100%); the ovarian fossa, confirmed in 8/12 cases (66.7%); and the uterosacral ligaments and posterior surface of the broad ligament, confirmed in 83/138 cases (60.1%). As for the other sites, the histologic confirmation rates in the ovarian surface, bowel serosa, and vesicouterine fold of the peritoneum were 48%, 40%, and 13%, respectively. CONCLUSION: Endometriosis has a multiple appearance, and the lesions may be confused with nonendometriotic lesions. It is clear that a nonhistology-based diagnosis may lead to unnecessary prolonged medical treatment and operations and may delay the proper treatment measures from being applied. Therefore, a meticulous histological confirmation should still be the first step in the laparoscopic diagnosis and treatment of suspected endometriosis.