Mycetoma is a common disease in the Republic of Niger. In two hospitals 133 cases were observed. The major site of lesions was the foot. Actinomycetomata were seen more often than eumycetomata. Streptomyces somaliensis is prevalent in the north desert zone while Actinomadura pelletieri is common in the southern part of the country. Madurella mycetomatis, the usual etiologic agent of eumycetoma, is seen in both regions. The species incidence and distribution in Niger differs from those of the west and east African endemic areas.