One hundred patients ages 1 month to 15 years received either ceftazidime (CZ) at a dose of 150 mg/kg/day divided every 8 hours or conventional treatment with chloramphenicol and ampicillin (CA). Seventy-eight had isolates recovered from the cerebrospinal fluid: 40 (51%) were Haemophilus influenzae (all ampicillin-susceptible); 16 (21%) were Streptococcus pneumoniae; 14 (18%) were Neisseria meningitidis; 3 (4%) were salmonellae; 1 (2%) was Pseudomonas; and 1 (2%) was Group B Streptococcus. Six patients with negative cerebrospinal fluid culture had positive latex agglutination (two H. influenzae, three N. meningitidis, one S. pneumoniae). Sixty-one patients had positive blood cultures. CZ inhibited 100% of H. influenzae at 0.78 micrograms/ml, S. pneumoniae at 0.39, N. meningitidis at 0.04 and salmonellae at 0.39 micrograms/ml. The mean peak serum concentration of CZ was 36.4 micrograms/ml with a mean cerebrospinal fluid level of 7.4 micrograms/ml. If one eliminates from the statistics those patients who died less than or equal to 24 hours after admission, five (10%) of 49 patients treated with CZ died, one (2%) improved and 43 (88%) were cured. Overall 29 patients died, 12 receiving CZ (20%) and 8 receiving CA (21%). There were no significant CZ-related toxicities. Gross neurologic sequelae were noted in 5% of 38 CZ patients and 4% of 28 CA patients. CZ compared favorably to CA for treatment of meningitis.