Five cases of airport malaria were observed in Geneva in the summer of 1989. All the patients lived within 2 km of Geneva-Cointrin International Airport. They were hospitalized between July 14 and August 2 for high fever. None had received a recent blood transfusion, an i.v. injection or traveled to a tropical country, except for one, a former pilot, whose last brief visit had been a year earlier. High minimum temperatures between July 6 and 10 in all likelihood allowed the survival of infected anopheles introduced by an aircraft. P. falciparum was identified in the blood smears of all the patients. Four had one or more symptoms of serious malaria and received intravenous treatment. In the fifth patient, treatment with cotrimoxazole for suspected acute pyelonephritis made diagnosis particularly difficult because the malaria infection was partially controlled by the antibiotic therapy. The time necessary for diagnosis of malaria varied from 5 to 31 days in the 5 cases. Airport malaria has been observed over the past twenty years in Europe, particularly in the summer, and is often serious because of late diagnosis and the type of plasmodium most frequently involved, P. falciparum. This diagnosis should be considered in patients with high fever of unknown origin, even when they have not travelled to an endemic zone.