OBJECTIVE: Our goal was to evaluate the performance of screening with (1) Papanicolaou and human papillomavirus (HPV) DNA testing and (2) Papanicolaou testing with reflex HPV testing of atypical squamous cells of undetermined significance for detecting cervical intraepithelial neoplasia grade 3 or more in clinics that serve low-income women in the United States. STUDY DESIGN: There were 4799 women who were recruited primarily from Planned Parenthood clinics and who were screened with liquid-based Papanicolaou testing and HPV DNA testing and referred for biopsy based on a positive test result for oncogenic HPV DNA or a Papanicolaou test that showed atypical squamous cells of undetermined significance or more. RESULTS: Among 931 women who were 30-50 years of age, the sensitivity of reflex HPV testing was 53.8% (range, 38.2%-72.3%). The sensitivity of HPV DNA and Papanicolaou testing was 91% (range, 74.6%-100%). The specificity of reflex HPV testing was 95.1% (range, 93.8%-96.3%). Generally, the specificity of HPV DNA and Papanicolaou testing was low. CONCLUSION: Among US women who are >or=30 years old, HPV DNA and Papanicolaou testing is a reasonable cervical cancer screening strategy.