Eighty-two patients with the acquired immunodeficiency syndrome (AIDS) were admitted to the intensive care units (ICUs) at San Francisco General Hospital (SFGH) between March 1981 and December 1985. Of these patients, 69% died in the hospital, as did 87% of patients who required mechanical ventilation because of Pneumocystis carinii pneumonia and respiratory failure. Although the number of hospital admissions of patients with AIDS has increased steadily since the fourth quarter of 1982 (12 admissions) through the fourth quarter of 1985 (158 admissions), the number of admissions to the ICUs peaked at 17 in the second quarter of 1984 and decreased steadily, averaging 5 per quarter in 1985. This decrease was not explained by a reduction in the number of patients with P. carinii pneumonia or an improvement in their treatment. A survey of physicians at SFGH indicated that physicians are aware of the poor prognosis of patients with AIDS with P. carinii pneumonia and respiratory failure, believe that mechanical ventilation is infrequently indicated for this condition, and have become increasingly likely to discuss issues of resuscitation with their patients with AIDS. Therefore, possible explanations for this trend in ICU utilization include changing physician attitudes, in addition to more effective patient counseling and increased availability of hospital and community-based support services that provide alternatives to terminal intensive care.