During a period of 21 months an analysis was made of bacteremia caused by Staphylococcus aureus in a teaching hospital for adults. During the observation period staphylococcal bacteremia was detected in 77 patients, i.e. in 1.83 cases per 1,000 admissions. Not less than 81.8% of staphylococcal bacteremia cases were hospital-acquired. The age-specific attack rate increased consistently from the sixth decade onwards. The male/female ratio was 1.96: 1. If this ratio was related to the sex ratio of patients admitted to the hospital during the observation period, statistical significance was reached for the surplus of males. Staphylococcal bacteremia contributed to death in 14 of 47 patients, i.e. 18.2%. Intravascular infection was the most prevalent source of infection (25 of 77 cases, i.e. 32.5%). Serious complications were observed in 14 cases of staphylococcal bacteremia. Eight of these patients had endocarditis and four died. Tolerance was observed with nine of 77 strains and may have influenced the reaction to antimicrobial therapy in at least one case.