Cefpodoxime proxetil (CS-807, CPDX-PR), a new cephalosporin antibiotic, was investigated for its usefulness in pediatrics. 1. The total number of patients treated were 21 with their ages ranging from 3 months to 9 years and 1 month, consisting of 5 male and 16 female infants. 2. Single dosages of the drug ranged between 4.4 mg and 5.8 mg/kg with oral administration for 3 times daily in fasting. A total aggregated dosage was between 46.4 mg/kg and 200.0 mg/kg. The length of administration was 3 to 12 days. 3. The breakdown of symptoms were 9 cases of acute pharyngitis, 5 cases of acute tonsillitis, 3 cases of acute bronchitis, and 1 case each of impetigo + purulent rhinitis, cervical lymphadenitis, scarlet fever, and urinary tract infection. 4. The clinical efficacy rate was 100% with 18 excellent responses and 3 good responses. 5. The bacteriological efficacy rate was 90.9% in eradication rate, based on results on 17 strains of suspected causative microorganism among which 10 strains were eradicated, 1 strain was decreased, and 6 strains were unknown. 6. There was no side effect during the treatment and after the discontinuation, while, in clinical laboratory tests, GOT and GPT were elevated in 1 case which was judged as abnormal. No patient refused the drug. CPDX-PR was considered to be very useful drug because of its excellent efficacy and safety in pediatrics in treating infectious diseases.