Pneumonia was the third leading admitting diagnosis at a large tertiary care hospital costing $12,653 per admission. The American Thoracic Society recommends the use of a ?-lactam with or without macrolide as the preferred antimicrobial regimen for patients with CAP admitted to a non-ICU. OBJECTIVE: The objective of this evaluation was to compare ceftriaxone alone (regimen 1) versus ceftriaxone plus macrolide (regimen 2) using length of stay, antibiotic costs, and total hospital charges from a hospital perspective. METHODS: The data were collected prospectively during December 1998 and May 1999. Fine et al 1998 defined risk scores for CAP and classified them into 5 categories: 1 (low risk) through 5 (high risk). Most of our patient population belonged to risk class 2. We compared 26 patients diagnosed with CAP and stratified into risk class 2. Thirteen patients received regimen 1 and 13 patients received regimen 2. RESULTS: We found statistically significant differences in hospital length of stay, antibiotic costs, and total hospital charges. Patients who received ceftriaxone alone had shorter lengths of stay (2.7 ? 1.9 days vs. 5.6 ? 3.9 days, p = 0.028), lower antibiotic costs ($93.02 ? $58.79 vs. $169.11 ? $108.81, p = 0.036), and lower total hospital charges per patient ($2,362.41 ? $1,442.18 vs. $4,431.42 ? $3,108.92, p = 0.040) than patients who received ceftriaxone plus macrolide. CONCLUSION: Ceftriaxone alone may be sufficient in the treatment of hospitalized CAP patients who are classified in risk class 2.