The major objective of the study was to determine if the contrasting frequencies (1.5% vs. 22%) of progression of cervical intraepithelial neoplasia (CIN) 3 lesions to invasive cervical carcinoma in two groups of patients in a previously published study from New Zealand had a virologic basis. Archival tissues on which the original diagnosis of CIN 3 was made were examined. Paraffin sections of 81 CIN 3 lesions from each group were tested for the presence of human papillomavirus (HPV)-6, -11, -16, and -18 DNA sequences by a combination of in of in situ hybridization for viral transcripts and polymerase chain reaction for viral DNA. The virologic profiles of the two groups were similar; HPV-16 and HPV-18 were identified, respectively, in 62% and 6% of CIN 3 lesions of group 1 and in 60% and 2% of CIN 3 lesions of group 2. additional tissues were examined for 17 women of group 2, who progressed from CIN 3 invasive cancer. Progression to invasive cancer was not associated with infection with specific HPV types. It is concluded that the contrasting frequencies of progression to invasive carcinoma in two groups of New Zealand women were not attributable to differences in HPV type distribution in the original CIN 3 lesions of these two groups.