Visceral leishmaniasis is rare in western Europe, but may be life-threatening in immunocompromised patients. It is therefore important to understand the incidence of the disease in a non-endemic area and its relationship with immunosuppressive conditions. Between 1990 and 2005, 12 patients were diagnosed with leishmaniasis at Basel University Hospital, Switzerland. Eleven presented with visceral symptoms and ten had an underlying immunosuppressive condition. Since increasing numbers of immunosuppressed patients have a history of travel to endemic countries, an association of visceral leishmaniasis with cellular immunosuppression (other than that associated with human immunodeficiency virus) might become more frequent in non-endemic areas.