Laboratory and clinical studies were carried out with T-1982 (cefbuperazone) in pediatric infectious diseases. Results were as follows. 1. The average serum concentrations of T-1982 following intravenous injection of 10 mg/kg and 20 mg/kg were 35.3, 64.7 micrograms/ml at 30 minutes, 25.5, 41.5 micrograms/ml at 1 hour, 12.4, 21.8 micrograms/ml at 2 hours, respectively. Dose-response was observed. Urinary recovery rates of T-1982 during 6 hours after injection of 10 mg/kg and 20 mg/kg were 57.3% and 73.6%, respectively. 2. The antibacterial activity of T-1982 against clinically isolated organisms was determined. T-1982 was more active than cefazolin and cefmetazole against K. pneumoniae, H. influenzae and E. coli. It was also effective against ampicillin-resistant E. coli. 3. Thirty-seven patients received daily 30-69 mg/kg of T-1982 t.i.d. for 5-9 days. The rate of satisfactory clinical response was 91.9%. 4. Side effects were diarrhea in 4 cases, diarrhea and rash in 1 case and slight elevation of GOT and GPT in 1 case. But these were transient and mild.