In 2007, the national prevalence of HIV in Kenya was 7.1% among persons aged 15-64 years, with provincial prevalence rates ranging from 0.8% in North Eastern Province to 14.9% in Nyanza Province. Although an estimated 85.0% of males in Kenya are circumcised, nearly half of all uncircumcised men live in Nyanza Province, where circumcision prevalence is only 48.2%. Based on the results of three randomized controlled trials in 2007 showing that medical male circumcision is effective in reducing HIV acquisition among men by approximately 60%, the World Health Organization and the Joint United Nations Programme on HIV/AIDS issued recommendations urging countries to offer male circumcision as an additional HIV prevention intervention. Kenya's Ministry of Health (MOH) prioritized the implementation of voluntary medical male circumcision (VMMC) services by targeting areas with low prevalence of male circumcision and high HIV prevalence. This report summarizes the progress of the VMMC scale-up in Kenya during 2008-2011. By December 2011, a total of 340,958 males had been circumcised in 260 CDC-supported sites.* Among those VMMCs, 280,713 (82.3%) were conducted in Nyanza Province. A total of 273,115 (80.1%) VMMC clients were aged ≥15 years, and 49,162 clients (14.4%) were aged ≥25 years. VMMCs performed among clients aged ≥25 years increased from 5,938 (11.9%) in 2009 to 24,945 (14.9%) in 2011. Providing VMMC services to males aged ≥25 years remains a key challenge to reaching Kenya's national target of 80% VMMC coverage among uncircumcised males aged 15-49 years by the end of 2013.