We studied 233 consecutive episodes of Staphylococcus aureus bacteremia in 230 patients between 1980 and 1984 at a community teaching hospital. Bacteremia was community-acquired in 78 episodes, acquired from nursing homes in 22 episodes and hospital-acquired in 133 episodes. The over-all mortality was 48.9%. Patients .gtoreq. 60 years had higher mortality (62.0%) than patients < 60 years old (25.3%). Hospital-acquired bacteremia was associated with a higher mortality (59.4%) than community-acquired bacteremia (29.5%). The respiratory tract as the portal of entry of bacteremia was associated with a higher mortality (80.4%), as compared to 53.5% when the portal of entry was undetermined, and 28.1% when the portal of entry was other sources. Increasing serum creatine levels were associated with increasing mortality: < 88.3 .mu.mol/l (26.5%), 97.2-168.0 .mu.mol/l (51.1%), and > 176.8 .mu.mol/l (67.9%). Increasing serum bilirubin levels were also associated with increasing mortality: < 17.1 .mu.mol/l (40.6%), 18.8-49.6 .mu.mol/l (57.1%), and > 51.3 .mu.mol/l (84.2%). Very high leukocyte counts were associated with higher mortality: > 20 .times. 109/l (73.9%), 10-20 .times. 109/l (37.4%), and < 10 .times. 109/l (45.8%).