Three cases of multiple opportunistic infections in previously healthy homosexual males were observed in 3 different University Hospitals in Switzerland. Two of the patients died. Infections were multiple, with P. carinii pneumonia (3 cases), chronic mucocutaneous ulcers probably due to Herpes simplex virus (2 cases), mucosal candidiasis (2 cases) and disseminated infections due to cytomegalovirus (1 case) and Mycobacterium avium (1 case). All patients had depressed cellular immunity with marked lymphopenia. These cases are similar to those recently observed in the United States, but two of the patients had never been to the USA although both had vacationed in Haiti where the syndrome has been described. These patients illustrate that this new syndrome should also be suspected outside the USA when a patient (especially a male homosexual) presents with persistent fever of unknown origin and develops opportunistic infections without obvious underlying disease.