Published in the Bulletin of the World Health Organization, this article reports the results of a prospective study of the safety of traditional and medical male circumcisions conducted in Kenya’s Bungoma District in July and August of 2004. More than 35 percent of the 443 men circumcised traditionally and almost 18 percent of the 99 men circumcised clinically experienced complications. The authors conclude that “extensive training and resources will be necessary in sub-Saharan Africa before male circumcision can be aggressively promoted for HIV prevention....Safety of circumcision in communities where it is already widely practised must not be ignored.”