To assess the role of p16( INK4A), bcl-2, and p53 in cervical cancer screening, we conducted a retrospective trial of prospectively collected data. Sixty two women with abnormal Pap smears were subjected to colposcopy and biopsies from any abnormal lesion. Human papillomavirus (HPV)-DNA typing, histology, and immunochemistry for p16(INK4A), bcl-2, and p53 were performed for these women. Histologic diagnosis was that of low grade squamous intraepithelial lesion (LSIL), high grade squamous intraepithelial lesion (HSIL), or cancer in all cases. Human papillomavirus strains were identified in 56 patients (90.3%). All HSIL and invasive cancer cases were HPV positive. p16(INK4A) immunostaining yielded 100% sensitivity, 76% specificity, 61% positive predictive value, and 100% negative predictive value in cancer patients. The corresponding performance indicators for HSIL patients were 75%, 62%, 32%, and 91%. bcl-2 and p53 expression did not correlate with worsening grades of cervical disease. We conclude that p16(INK4A) seems to be a sensitive biomarker of high grade cervical intraepithelial neoplasia and cancer.