OBJECTIVE.: To study the prevalence of human papillomavirus 16/18 types among sexually active young women. STUDY DESIGN.: From October 1998 until May 1999 we examined 160 women between the ages of 15 and 24 (mean = 19.5 +/- 2.5) years. Histology and colposcopy verified diagnoses of cervical pathology were present in 19 cases (11.9%) of cervical intraepithelial neoplasia (CIN) 1,2. At each visit, we collected information about lifestyle and sexual behavior. Human papillomavirus-DNA typing of cervical scrapes was performed by polymerase chain reaction. RESULTS.: Positive results of DNA test were present in 39 cases (24.4%): 27 of 141 with cytologically normal women (19.1%), 12 of 19 with CIN 1,2 (63.2%). An increased risk of human papillomavirus infection was significantly associated with increased number of vaginal-sex partners and smoking. A protective effect was noted from the use of condoms. CONCLUSIONS.: This data showed a high frequency of human papillomavirus 16/18 infection.