OBJECTIVE: To determine the overtreatment rate at colposcopy in women who underwent a see-and-treat protocol. METHODS: We identified 3,192 patients (mean age 36 years, standard deviation 8.7) who underwent a see-and-treat protocol in Radboud University Nijmegen Medical Center between January 1981 and December 2010. Overtreatment, defined as cervical intraepithelial neoplasia 1 or less at final histopathology analysis, was investigated in relation to the age of the women, time of referral, cervical smear result, colposcopic impression, and histopathology result. RESULTS: A total of 579 women (18.1%, 95% confidence interval [CI] 16.7-19.5) were overtreated. The lowest overtreatment rate (4.5%, 95% CI 3.5-5.5) was seen in women with both a high-grade cervical smear result and a high-grade colposcopic impression. Women aged younger than 40 years were less likely to be overtreated (13.1%, 95% CI 11.7-14.5) than women aged 40-49 years (24.2% 95% CI 21.2-27.4, number needed to harm nine) and aged 50 years and older (42.2%, 95% CI 36.5-47.7, number needed to harm three). CONCLUSIONS: The overtreatment rate is low for patients with both a high-grade smear result and a high-grade colposcopic impression, justifying a see-and-treat approach for these patients. In women with either a high-grade smear result or a high-grade impression on colposcopy, a see-and-treat approach may still be preferable but has higher overtreatment rates. Given the side effects of cervical surgery on pregnancy outcome, young women, in particular those who have either a low-grade smear result or low-grade impression on colposcopy, are better served by a two-step approach. In older women, a see-and-treat policy may be preferable.