Located in the Indian ocean, Reunion island, a French overseas territory, is free of malaria since the 1960's. As malaria is still highly endemic in the neighbouring countries, imported cases are averaging 130 to 150 cases per year. From 1993 to 1996, about 483 cases of imported malaria were admitted in Reunion. Five severe complicated Plasmodium falciparum malaria cases occurring in non-immune persons, required further treatment in the intensive care unit (age 40 +/- 8 years, duration: 14.8 +/- 7.4, SAPS: 21 +/- 10). Three patients died. As short-stay travellers, patients were contaminated in Madagascar (4) and in Malawi (1) and presented with an associated pathology: alcohol and tobacco abuses (2 cases), AIDS (1 case). In all cases, chemoprophylaxis was either inadequate (chloroquine alone, 3 cases) or absent (2 cases) and the diagnosis and the appropriate treatment were delayed. Moreover, patients were either self-treating themselves, or initially refused to be admitted. Parasitemia was very high. Two patients died within an hour following their admission before diagnosis could be made and quinine treatment be initiated (rupture of the spleen, multiple organ failure). One patient died at day 7 (acute respiratory distress syndrome, renal failure). Two survived under respiratory assistance and hemodialysis and presented the usual intensive care complications (respiratory nosocomial infection, acute cholecystitis). In Réunion island, imported P. falciparum still accounts for a high rate of morbidity and few fatalities, despite a sophisticated curative health system. Delay in diagnosis and institution of an appropriate treatment is frequent in non-immune persons who develop fever and non-specific symptoms. It markedly increases the risk of complications and death from falciparum malaria as well as morbidity cofactors. Emphasis must be placed on appropriate information of health personnel and travellers.