A total of 410 colposcopic examinations were performed on 188 female cebus monkeys that were under study to determine the oncogenic potential of herpes simplex virus type 2 in this genus. A split-cone vaginal speculum was developed that permitted good observation of the vaginal cervix in the cebus monkey. The cervical anatomy of cebus monkeys was found to differ from that of humans in that the surface of the animal cervix was more papilliform, with thinner squamous epithelium, and the squa-mocolumnar junction lay within the cndocervical canal. Therefore, the ability to detect abnormalities in the cervical epithelium by colposcopic examination in the cebus monkey was restricted to vascular changes in the squamous epithelium. After 100 examinations, several vascular patterns were distinguishable and interpretations of these patterns were compared with cytologic findings on the same animals. Findings by both cytology and colposcopy were mild in nature; no carcinoma was detected. Colposcopic and cytologic findings correlated at a level of 84%. More abnormalities were detected with colposcopy than with use of cytologic techniques.