BACKGROUND: Approximately one in three men are circumcised globally, but there are relatively few data on the safety of the procedure. The aim of this paper is to summarize the literature on frequency of adverse events following pediatric circumcision, with a focus on developing countries. METHODS: PubMed and other databasess were searched with keywords and MeSH terms including infant/newborn/pediatric/child, circumcision, complications and adverse events. Searches included all available years and were conducted on November 6th 2007 and updated on February 14th 2009. Additional searches of the Arabic literature included searches of relevant databases and University libraries for research theses on male circumcision.Studies were included if they contained data to estimate frequency of adverse events following neonatal, infant and child circumcision. There was no language restriction. A total of 1349 published papers were identified, of which 52 studies from 21 countries met the inclusion criteria. The Arabic literature searches identified 46 potentially relevant papers, of which six were included. RESULTS: Sixteen prospective studies evaluated complications following neonatal and infant circumcision. Most studies reported no severe adverse events (SAE), but two studies reported SAE frequency of 2%. The median frequency of any complication was 1.5% (range 0-16%). Child circumcision by medical providers tended to be associated with more complications (median frequency 6%; range 2-14%) than for neonates and infants. Traditional circumcision as a rite of passage is associated with substantially greater risks, more severe complications than medical circumcision or traditional circumcision among neonates. CONCLUSIONS: Studies report few severe complications following circumcision. However, mild or moderate complications are seen, especially when circumcision is undertaken at older ages, by inexperienced providers or in non-sterile conditions. Pediatric circumcision will continue to be practiced for cultural, medical and as a long-term HIV/STI prevention strategy. Risk-reduction strategies including improved training of providers, and provision of appropriate sterile equipment, are urgently needed.