The treatment of bacterial pneumonia commands a large segment of hospital resources, and economic concerns are dictating shorter hospital stays. This study was designed to determine whether outpatient therapy with intravenous (IV) antibiotics (a third-generation cephalosporin, cefotaxime, delivered via an ambulatory delivery system [ADS]) is as effective as traditional hospital management of pneumonia. A subgroup of 62 patients from three centers, with bacterial pneumonia, were enrolled in a multicenter, open-label study of outpatient IV cefotaxime therapy. Doses of cefotaxime were 1 g IV every 12 hours, 1 g IV every 8 hours, or 2 g IV every 8 hours, based on severity of infection. Of 62 patients, 53 (85%) completed the study. All 22 bacteriologically evaluable patients showed eradication of pathogen or clinical cure with no obtainable follow-up culture; no relapses, reinfections, or superinfections were reported. Overall clinical success rate was 94.8% (satisfactory 75.9%; improved 19.0%, n = 58). Average length of hospital stay was 2.3 +/- 4.83 days. In conclusion, clinical success rates with outpatient IV cefotaxime therapy were comparable to previous studies with IV cefotaxime for pneumonia treatment in the hospital. Outpatient IV antibiotic therapy has the potential to significantly reduce length of hospital stay for pneumonia without sacrificing clinical efficacy.