The 185 hospitalized patients (aged 19 to 95 years) with pneumonia were randomly assigned to receive 500 mg of cefuroxime axetil (250 mg q12h), 1,000 mg of cefuroxime axetil orally (500 mg q12h), or 1,500 mg of cefaclor orally (500 mg q8h), daily, for a mean of nine days. Among the 151 evaluable patients, clinical cure was noted in 58% of the 500-mg cefuroxime axetil group, 94% of the 1,000-mg cefuroxime axetil group, and 88% of the cefaclor group, and clinical improvement in 32%, 4%, and 9%. Bacteriologic outcome was similar in the three groups. Adverse events were minor and comparable among the treatment groups. Cefuroxime axetil is a safe and effective oral antimicrobial for the treatment of pneumonia in adults.