In April 1993 a national survey of pneumococcal bacteremia in hospitalized Israeli adults was started, and this survey covered 23 of the 24 Israeli medical centers. During the first 2 years, 603 episodes of pneumococcal bacteremia were recorded. The overall annual incidence of pneumococcal bacteremia in Israeli adults was 14.5 episodes per 100,000 inhabitants, and the overall mortality rate was 27.8%. Pneumonia was the source of bacteremia in 70.8% of cases, primary bacteremia was the source in 17.5%, meningitis was the source in 7.5%, and otitis media/sinusitis was the source in 4.2%. Of the 258 pneumococcal isolates for which an MIC was determined, 88.8% were susceptible to penicillin, 9.3% were partially resistant, and only 1.9% were highly resistant. Twenty-four serogroups were identified from 398 strains tested. The highest percentage of penicillin-resistant strains belonged to serogroups 23, 19, 9, 4, and 6. Although only 13 of these 24 serogroups correspond to the serotypes included in the 23-valent pneumococcal vaccine, they accounted for 94% of all isolates.