Medical records of 134 patients with Staphylococcus aureus bacteremia at the Cincinnati General Hospital during 1975-1977 were reviewed. Bacteremia was community-acquired in 48 patients and hospital-acquired in 73 patients. In addition, 13 patients were on chronic hemodialysis. In 22 patients, bacteremia was associated with an infected intravenous catheter; all except one of these patients acquired the infection in the hospital. Thus 21 of 73 (29%) episodes of hospital-acquired S aureus bacteremia were associated with an infected intravenous catheter. Four of the 22 patients with intravenous catheter-associated bacteremia had endocarditis (18%). The overall incidence of endocarditis in this study was 16% (21 of 134 patients). This contrasted with the much higher incidence of endocarditis (64%) in Staphylococcal bacteremia reported from this same hospital in patients during 1940-1954. Possible reasons for this difference are discussed.