The optimal management of squamous atypia on cytology has not been determined. Colposcopy has been recommended because of the high false-negative rate of cytology. To evaluate colposcopy, 1,074 consecutive, nonpregnant women presenting with squamous atypia on cytology were examined prospectively with colposcopy and simultaneous repeat cytology. No specific treatment was given prior to evaluation. Biopsy and endocervical curettage were performed when clinically indicated. Two hundred two women (18.8%) had abnormal cervical or vaginal biopsies, 74 had human papillomavirus, and 128 had cervical intraepithelial neoplasia with or without associated papillomavirus infection. Invasive cancer was not detected. Repeat cytology suggested intraepithelial neoplasia in 60 women, 37 (61%) of whom had positive biopsy findings. Such biopsy findings were obtained in 89 of 306 women (29.1%) with repeat squamous atypia on cytology and in 76 of 708 women (10.8%) with repeat negative cytology. When the data were stratified in terms of age, 184/787 (19.6%) abnormal biopsies occurred in women less than or equal to 40 years of age and 18/287 (6.3%) in women greater than or equal to 41. Squamous atypia on cytology should not be ignored. However, women greater than or equal to 41 are at lower risk of having colposcopically detectable abnormalities and can be followed more conservatively.