Human papillomavirus (HPV) was detected by non-isotopic subgenomic probes on Southern blot hybridization (Oncor Inc., Gaithenberg, MD). The 108 samples which were obtained from patients below the age of 30 (mean age 19.0 +/- 2.8 yrs). All samples were collected from the ectocervical mucosa by Cytobrush (Medscand, Malmö, Sweden) as previously described. HPV-DNA was detected in 16 cases (15%). In 36 cases (33%) the patients presented clinical findings of condyloma or cervical intra-epithelial neoplasia (CIN) at simultaneous vaginal ectocervical smears. HPV-DNA was detected in 12 out of 36 cases. On the other hand, in the patients without subclinical findings HPV-DNA were detected in only 4 out of 70 cases (6%). HPV-DNA was detected in one of the 4 patients with accuminate condyloma of the cervix and in 4 out of 16 cases with similar lesions in the vulva. The only HPV type found in these patients was type 6. Papillomavirus was also detected in 5 out of 16 cases (31%) with flat condylomas, most studied types being represented here. CIN was only reported two patients both of them carrying HPV-DNA (types 16 and 18 respectively). The most common type of virus was HPV 6. Combined infections with two or three types were seen in 5 out of 16 HPV-positive cases (31%). Such cases are readily detected and typed with the present Southern blot procedure, where the use of subgenomic probes enables the distinction of all types, even when present in the same sample.