Leishmanioses are widespread in 88 countries of the tropical and subtropical zone, including regions of the Mediterranean Sea basin of Southern Europe. Actually, approximately 350 million of people live in Leishmania endemic areas and about 12 million of individuals are infected. Visceral leishmaniosis (kala-azar disease, tropical splenomegaly) is caused by at least 3 species of Leishmania protozoa: L. donovani, L. infantum and L. chagasi. The incidence of the disease is estimated at 500,000 new cases annually. The infection is transmitted by Phlebotomus or Lutzomyia mosquitos bites, in which intestines forms invasive to humans are developed. Leishmania spp. have a predilection to the reticulo-histiocytary system cells, leading to their proliferation and disruption, and after spreading to the circulation they invade spleen, liver and bone marrow. Visceral leishmaniosis should be suspected in travelers returning from tropical and subtropical areas with signs of splenomegaly and twice temperature spikes in a day. We reported a case of the kala-azar disease in the 22 year-old Polish patient seasonally working in Italy. The clinical picture was expressed by two daily pikes of fever proceeded by chills, excessive sweat, hepatosplenomegaly, lymphadenopathy, general weakness, abdominal pain and nausea. The Leishmania infection was complicated by candidiosis. Laboratory tests showed anaemia, thrombocytopenia, leucopenia, hypergammaglobulinaemia and a suppression of immunological cellular response. The diagnosis was confirmed by a presence of amastigota forms in macrophages of the bone marrow aspirate and a detection of specific antibodies to L. infantum by Westernblotting. The patient was successfully treated with Glucantime.