Correlates of HPV amongst a cohort of women with a CIN I detected by a screening Pap test were investigated. Co-incident CIN II/III lesions were identified and their influence on the HPVstatus and HPV determinants of screening detected CINI was assessed. Based on both the colposcopic impression and repeat Pap test, 537 women referred for examination of a Pap test classified as CIN I were triaged into two groups. Group A lesions were assessed as </= CIN I; n = 342 (63.7%) and group B as >/= CIN II; n = 195 (36.3%). Clinical, demographic, reproductive, and risk factor for cervical cancer correlates were collected. HPV typing of cervical scrapes collected at the colposcopic examination was done by PCR amplification using seven sets of type specific and one set of consensus primers. HPV positivity was identified in 47% of all scrapes; types 16/18 (28%), 31/33/35 (10%), 6/11 (2%), and unknown (7%). The HPV status of the cohort and group A were very similar. Group B had a slightly higher rate of HPV positivity (52%) due to an increase in types 16/18. Statistically significant correlates of HPV prevalence or type were not identified either for the entire group or both triage groups, however in each group, HPV positive women tended to be younger and to have more sexual partners. Co-incident CIN II/III spuriously increased the HPV prevalence rate of CIN I detected by a screening Pap test. The HPV appears to be sexually transmitted both in low and high grade lesions and explains why the HPV determinants of the entire cohort were unaffected by the co-incident CIN II/III.