Has there been a change in the duration of periods of hospitalization during the first two years after diagnosis of AIDS between patients diagnosed before 1988, compared with patients diagnosed since 1988? A cohort of 212 AIDS patients was studied. They were diagnosed before December 31, 1990 and were hospitalized between January 1, 1981 and March 31, 1993 in the University Hospital of Geneva, Switzerland. Overall, the duration of hospitalization did not seem to differ according to the year of AIDS diagnosis, though the more recently diagnosed patients were hospitalized with a more advanced level of immunosuppression. However, the pattern of hospitalization was slightly different. The periods of hospitalization for subjects diagnosed before 1988 were relatively longer soon after the AIDS diagnosis and at a late stage in the course of the disease, whereas for the more recent patients the lengths of hospital stays were more uniform during the whole course of the disease.