Questionnaires were distributed to homosexual and bisexual male participants in the Multicenter AIDS Cohort Study and to homosexual and bisexual male patients with acquired immunodeficiency syndrome (AIDS) to determine whether the men believed they had been refused medical or dental treatment because of their sexual orientation or a condition related to the human immunodeficiency virus (HIV). Men with AIDS were significantly more likely (18%) to report being refused treatment by a doctor or dentist on the basis of a known or suspected HIV-related condition than were men who were seropositive (5%) or seronegative (1%). Significantly more respondents reported refusal of dental care than of medical care.