Objective: To evaluate the effectiveness of screening using visual inspection with acetic acid (VIA). Methods: In a low-resource area of Peru in 2005-2008, a randomly selected sample of women who had previously screened negative by VIA and Pap (intervention group), and a group of eligible women previously unscreened by VIA (comparison group) were screened by VIA. The outcome measures were histologically confirmed cervical intraepithelial neoplasia (CIN) 2-3 and invasive cervical cancer. Results: There were 4252 women in the intervention group and 4392 in the comparison group. Histologically confirmed CIN 2 or worse was diagnosed in 31 (0.7%) and 115 (2.6%) women, and invasive cancer was diagnosed in 4 women (0.09%) and 43 women (1.00%), in the intervention and comparison groups, respectively. The adjusted odds ratio was 4.2 (95% confidence interval [CI], 2.7-6.4) for CIN 2 or worse, and 13.9 (95% CI, 4.9-39.6) for invasive cervical cancer in the comparison group. Conclusion: A lower prevalence of CIN 2-3 and invasive cervical cancer was seen in women previously screened by VIA, as compared with women not previously screened by VIA, implying that a single VIA screening can lower the population risk for cervical cancer. © 2011 International Federation of Gynecology and Obstetrics. Published by Elsevier Ireland Ltd. All rights reserved.