A retrospective study of 227 patients presenting with abnormal cervical cytology was conducted to investigate the relationship between human papillomavirus (HPV) and progression of untreated cervical intraepithelial neoplasia (CIN) lesions. All patients had colposcopically directed biopsies for histologic diagnosis. The patients were followed cytologically and colposcopically for a mean of 19 months (range 6-42 months). Progression of a cervical lesion was defined as progression to a higher CIN grade confirmed histologically by directed biopsy. HPV DNA detection was done on material remaining from the cervical swabs by the general primer polymerase chain reaction (PCR) and type-specific PCR method, which made the detection of HPV types 6, 11, 16, 18, 31, 33 and not yet sequenced DNA types (X) possible. The presence of HPV DNA increased with the severity of the lesion (P < 0.001). In CIN III, a 100% HPV DNA prevalence was found, with HPV type 16 being the most prevalent type in 75%. Progression was significantly related to the presence of HPV DNA, in particular HPV type 16. The percentage of progressive disease was 21% in the case of HPV DNA positive lesions (n = 130) and 29% in the presence of HPV type 16, whereas HPV DNA negative lesions (n = 97) showed no progression. The detection of HPV DNA and HPV genotype can be used to identify patients with high-risk cervical lesions, since the presence of HPV DNA and genotype 16 in particular are closely related to CIN progression.