Leprosy affects Africa and several islands in the Indian Ocean where it is endemic, such as Mayotte. An analysis of data collected between 2006 and 2011 describes the progression of the disease on the island of Mayotte. The data were collected by the Mayotte Hospital Center from bacteriologically confirmed cases for which a paucibacillary or multibacillary status had been established. From 2006 to 2011, 307 new cases of leprosy were diagnosed in Mayotte. The average annual detection rate was 2.6 per 10,000 inhabitants, and the prevalence was 5.0 per 10,000. In 2009, multibacillary forms became predominant and reached 87.2% in 2011. The prevalence recorded in 2011 (3.7 per 10,000) is the lowest since 1994, with 39 new cases, including 8 imported cases (1.8 cases per 10,000 inhabitants). The under-15 age group accounted for 26%. In 18 cases, the clinical form observed was lepromatous. Mayotte remains the French department most affected by leprosy. The increase in the proportion of multibacillary forms highlights active circulation of the bacillus. Leprosy is endemic in Mayotte and likely underestimated. It is important to strengthen leprosy control and surveillance in Mayotte in order to eliminate this disease. (R.A.)