American histoplasmosis, characterized by its small parasitological forms, is a visceral mycosis which though rare, has already been reported in Zaïre. A new case, in a girl of 4 years is reported with bad general condition, fever and general reaction of the reticulo-endothelial system. The microscopic aspects of the yeast are given. A treatment with ketoconazole proved rapidly effective and the patient had apparently recovered when she died of measles which have in Africa and specially in fragile patients a particular severity.