To investigate the prevalence and determinants of human papillomavirus (HPV) infection, the primary cause of cervical cancer, we studied 1741 women >/=15 years of age from Lampang and Songkla, Thailand. Exfoliated cervical cells were collected for Papanicolaou smear screening and DNA detection of 36 different HPV types. Serum immunoglobulin G antibodies against L1 virus-like particles (anti-VLPs) of HPV-16, -18, -31, -33, and -58 were evaluated using enzyme-linked immunosorbent assay. Overall, 110 women (6.3%) were HPV DNA positive; the most common types were HPV-16, -52, and -72. The age-standardized prevalence of HPV DNA was higher among the 1035 women from Lampang (9.1%; 95% confidence interval [CI], 7.1-11.1) than among the 706 women from Songkla (3.9%; 95% CI, 2.3%-5.6%). Anti-VLPs were found in 21.8% of all women and were more frequent among women from Lampang (29.2%) than among women from Songkla (10.9%). Major risk factors for cervical HPV DNA were age <35 years, HSV-2 seropositivity, and having a husband with extramarital sexual partners.