Regarded as infrequent, endometriosis of the cervix probably occurs more commonly than is generally realized. The lesion's apparent rarity may be ascribed to limited awareness of the clinical appearance, combined with technical difficulty in obtaining suitable biopsy material for confirmation. A consequence of previous cervical trauma, endometriosis of the cervix can be expected to increase in incidence with more widespread use of invasive cervical procedures. Clinical recognition and tissue confirmation thus become essential. This paper refocuses attention on cervical endometriosis by documenting the clinical, colposcopic, and histopathologic findings in 16 cases seen at a single colposcopy clinic over a 6-month period. Diagnosis in these patients was facilitated and improved by fine needle aspiration cytologic testing. This technique, not previously used for documentation of endometriosis in this location, is outlined in detail, together with a full description and illustration of the cytologic features.