A retrospective cohort study was conducted to determine whether the incidence of leprosy varied with the duration of antiretroviral therapy (ART). Between 1992 and 2006, seven cases of leprosy were observed. The incidence of leprosy in untreated patients was 0.7 per 1000 person-years, 13 per 1000 person-years in persons receiving HAART for more than 3 months and 0.9 per 1000 person-years for persons receiving HAART for more than 3 months. The adjusted hazard ratio was 18.5 (95% confidence interval, 1.6-217) with P = 0.02. In tropical areas where HAART is increasingly available, physicians should be aware of the possibility of incident leprosy shortly after HAART initiation.