Observations of 12 patients with AIDS at this institution from March 1981 to April 1984 are reported. Ten patients were homosexuals and two were bisexual. The majority had travelled abroad (USA, Haiti) and reported multiple anonymous sexual contracts. Eleven patients reported symptoms and signs, of 2-12 months' duration, frequently seen in pre-AIDS: fatigue (10), weight loss (10), diarrhea (7), night sweats (5), fever (4), and generalized lymphadenopathy (1). Laboratory studies showed anemia (10), lymphopenia (9), leukopenia (7), decreased T-helper/T-suppressor ratio (10) and cutaneous anergy to multiple skin-test antigens (9). P. carinii pneumonia was diagnosed in three patients, P. carinii pneumonia and Kaposi's sarcoma in one patient and Kaposi's sarcoma in six patients. Another patient had a chronic mucocutaneous infection with herpes simplex and another an intestinal cryptosporidiosis and Kaposi's sarcoma. Alpha-A-interferon was used to treat patients with Kaposi's sarcoma and three patients with limited disease showed a favorable response. Six patients with advanced disease died.