BACKGROUND: Several sub-Saharan African countries plan to scale-up infant male circumcision (IMC) for cost-efficient HIV prevention. Little data exist about the safety of IMC in East and southern Africa. We calculated adverse event (AE) rate and risks for AEs associated with introduction of IMC services at five government health facilities in western Kenya. METHODS: AE data were analyzed for IMC procedures performed between September, 2009 and November, 2011. Healthy infants aged ≤ 2 months and weighing ≥ 2.5 kg were eligible for IMC. Following parental consent, trained clinicians provided IMC services free of charge under local anesthesia using the Mogen clamp. Odds ratios and 95% confidence intervals were used to explore AE risk factors. FINDINGS: A total of 1,239 IMC procedures were performed. Median age of infants was 4 days (IQR=1, 16). The overall AE rate among infants reviewed post-operatively was 2.7% (18/678; 95%CI: 1.4, 3.9). There was one severe AE involving excision of a small piece of the lateral aspect of the glans penis. Other AEs were mild or moderate and were treated conservatively. Babies one month of age or older were more likely to have an AE (OR 3.20; 95%CI: 1.23, 8.36). AE rate did not differ by nurse versus clinical officer or number of previous procedures performed. CONCLUSION: IMC services provided in Kenyan Government hospitals in the context of routine IMC programming have AE rates comparable to those in developed countries. The optimal time for IMC is within the first month of life