Following a case of cardiac tamponade in a patient with the acquired immunodeficiency syndrome (AIDS), we examined the frequency and clinical spectrum of pericardial effusions associated with human immunodeficiency virus infection (HIV) at our institution. Of 187 hospitalized patients documented to have pericardial effusions over a one-year period, 14 (7 percent) were known to be HIV-positive at the time of their echocardiograms. One patient presented with a large effusion and cardiac tamponade, three had moderate effusions, and ten had small effusions. The probable effusion etiology was established in four cases and included endocarditis (2), lymphoma (1), and myocardial infarction (1). In hospital mortality was 29 percent (4 of 14). From our study, as well as a growing number of reports in the literature, we conclude that HIV-associated pericardial effusions are frequently seen and that their clinical spectrum is broad.