Minority women in the United States experience a disproportionately high burden of the more than 2 million yearly cases of squamous intraepithelial lesions of the cervix. Risk factors for squamous intraepithelial lesions of the cervix are infection with the sexually acquired human papillomavirus (HPV), an early age at first intercourse, history of multiple sexual partners, oral contraceptive use, high parity, lower socioeconomic status, poor diet, immunosuppression, and promiscuous male sexual partners. Although Hispanics are the largest growing minority population in the United States, few HPV risk factor studies have either included or focused on Hispanics in the United States. To determine risk factors for HPV infection among Mexican-American women, we conducted a cross-sectional study from 1992-1995. Nine hundred and seventy-one women, 18-47 years of age, with cytology results were included in this analysis. Overall, 13.2% of participants were HPV positive by the Hybrid Capture tube method for high-risk types 16, 18, 31, 33, 35, 45, 51, 52, or 56. Age [adjusted odds ratio (AOR) = 0.3 for ages >36 years compared with ages 18-20] and duration of oral contraceptive use (AOR = 0.4 for > or =4 years relative to nonusers) were inversely associated with these high-risk types of HPV infection. Marital status (AOR = 1.9 among single women compared with married) and lifetime number of sexual partners (AOR = 2.3 for women > or =5 partners relative to monogamous women) were positively associated with an increased risk. Participants born in Mexico were significantly (P < 0.05) older, had fewer sex partners, and older age at first intercourse. Despite this lower behavioral risk profile, women born in Mexico were significantly more likely (AOR = 1.9; CI = 1.2-3.2) to have an HPV infection compared with United States-born, Mexican-American women after adjustment for potential confounders. Collectively, these results suggest that an unmeasured factor, such as the sexual behavior of the male partner, may be influencing HPV risk. Further research is needed to define this factor and to assess cultural norms of sexual behavior.