Adenocarcinoma of the cervix has been associated with oral contraceptive use, often prolonged. The clinicopathologic features of seven cases of endocervical neoplasia in long-term combination pill users, all 33 years of age or younger, were reviewed and compared with seven cases in nonusers. Duration of drug use ranged from 4.5 to nine years. Adenocarcinoma in situ was found in all cases either in pure form or associated in invasive adeno- or adenosquamous carcinoma; squamous carcinoma in situ (CIS) was seen in two cases, one of which showed focal microinvasion. Hypersecretory changes were seen in adjacent endocervix in two cases but the morphology of neoplastic lesions was similar to that unassociated with pill use. The possible role of chronic hormonal stimulation in cervical carcinogenesis is discussed in light of these findings and current epidemiologic data.