Context: Recent cervical cancer screening guidelines state that the interval between screenings can be safely extended to 3 years in healthy women 30 years or older who have normal cytology results and have negative test results for oncogenic human papillomavirus (HPV)-DNA. Objective: To determine the incidence of squamous intraepithelial lesions (SILs) in HIV-seropositive women with nor mal cytology results, by baseline HPV DNA results. Design, Setting, and Patients: Participants were HIV-seropositive (n = 855; mean age, 36 years) and HIV-seronegative (n = 343; mean age, 34 years) US women with normal baseline cervical cytology who were enrolled in the Womens Interagency HIV Study (WIHS), a large, multi-institutional prospective cohort study. Since their recruitment during 1994-1995, WIHS participants have been followed up semi-annually with repeated Pap smears for a median of 7 years. Main Outcome Measure: The cumulative incidence of any SIL and high-grade SIL or cancer (HSIL+) was estimated according to baseline HPV DNA results, stratified by HIV serostatus and CD4 T-cell count. Results: Development of any SIL in women with negative HPV results (both oncogenic and nononcogenic) at 2 years was as follows: in HIV-seropositive women with CD4 counts less than 200/μL, 9%(95%CI, 1%-18%); with CD4 counts between 200/μL and 500/μL, 9%(95%CI, 4%-13%); and with CD4 counts greater than 500/μL, 4%(95%CI, 1%-7%). The CIs for these estimates overlapped with those for HIV-seronegative women with normal baseline cytology who were HPV-negative (3%; 95%CI, 1%-5%), indicating that at 2 years, there were no large absolute differences in the cumulative incidence of any SIL between groups. Furthermore, no HPV-negative participants in any group developed HSIL+lesions within 3 years. Multivariate Cox models showed that on a relative scale, the incidence of any SIL among HIV-seropositive women with CD4 counts greater than 500/μL (hazard ratio [HR], 1.2; 95%CI, 0.5-3.0), but not those with CD4 counts less than or equal to 500/μL (HR, 2.9; 95%CI, 1.2-7.1), was similar to that in HIV-seroneg-ative women. Conclusion: The similar low cumulative incidence of any SIL among HIV-seronegative and HIVseropositive women with CD4 counts greater than 500/μL and who had normal cervical cytology and HPV-negative test results suggests that similar cervical cancer screening practices may be applicable to both groups, although this strategy warrants evaluation in an appropriate clinical trial. Context: Recent cervical cancer screening guidelines state that the interval between screenings can be safely extended to 3 years in healthy women 30 years or older who have normal cytology results and have negative test results for oncogenic human papillomavirus (HPV) -DNA. Objective: To determine the incidence of squamous intraepithelial lesions (SILs) in HIV-seropositive women with nor mal cytology results, by baseline HPV DNA results. Design, Setting, and Patients: Participants were HIV-seropositive (n = 855; US women with normal baseline cervical cytology who were enrolled in the Women’s Interagency HIV Study (WIHS), a large, multi-institutional prospective cohort study. Since their recruitment (n = 343; mean age, 34 years) During 1994-1995, WIHS participants have been followed up semi-annually with repeated Pap smears for a median of 7 years. Main Outcome Measure: The cumulative incidence of any SIL and high-grade SIL or cancer (HSIL +) wa Results: Development of any SIL in women with negative HPV results (both oncogenic and nononcogenic) at 2 years was as follows: in HIV-seropositive women with CD4 counts less than 200 / μL, 9% (95% CI, 1% -18%); with CD4 counts between 200 / μL and 500 / μL, 9% The CIs for these estimates overlap with those for HIV-seronegative women with normal baseline cytology who were HPV-negative (3%; 95% CI, 1% to 7% % CI, 1% -5%), indicating that at 2 years, there were no large absolute differences in the cumulative incidence of any SIL between groups. Furthermore, no HPV-negative participants in any group developed HSIL + lesions within 3 years. Multivariate Cox models showed that on a relative scale, the incidence of any SIL among HIV-seropositive women with CD4 counts greater than 500 / μL (hazard ratio [HR], 1.2; 95% CI, 0.5-3.0), but no t those with CD4 counts less than or equal to 500 / μL (HR, 2.9; 95% CI, 1.2-7.1), was similar to that in HIV-seroneg-ative women. seronegative and HIVseropositive women with CD4 counts greater than 500 / μL and who had normal cervical cytology and HPV-negative test findings suggest that similar cervical cancer screening practices may be applicable to both groups, although this strategy warrants evaluation in an appropriate clinical trial.