We studied 390 consecutive episodes of Staphylococcus aureus bacteremia in the four nonuniversity hospitals of one metropolitan area between 1977 and 1981. Overall mortality was 31%, with 52% of deaths being attributed to the infection. The 4.9% incidence of recognized endocarditis was lower than that previously reported. Although 41% of deaths occurred by the end of the third day after positive blood cultures had been obtained, choice of antimicrobial therapy bore no apparent relationship to eventual clinical outcome.