Cyclospora cayetanensis is a protozoan responsible for cyclosporosis, it is a digestive coccidiosis in the tropical and intertropical area. The human being constitutes the only reservoir and his transmission is related to the fecal content based on the ingestion of water and / or food contaminated by infectious oocysts. This infection is mainly responsible for watery diarrhea which can be severe in immunocompromised patients. We report a case of a little girl with acute lymphoid leukemia type B in whom we diagnosed a digestive infection with Cyclospora cayetanensis.