We interviewed 49 women who had a history of condyloma acuminatum and 196 age-matched controls. For women who had ever smoked, the risk of developing condyloma was 3.7 times that of women who had never smoked (95% confidence interval, 1.8-7.6). The relative risk associated with long-term use (five or more years) of oral contraceptives was 9.8 (95% confidence interval, 1.5-65.6). Condyloma acuminatum is caused by infection with human papilloma virus (HPV), usually types 6 or 11. Infection with HPV, most commonly of other types, is associated with an increased risk of cervical neoplasia. If smoking and oral contraceptives increase the risk of infection with these other types of HPV as they do with types 6 and 11, this factor could be the means by which smoking and long-term use of oral contraceptives increase the incidence of cervical neoplasia.