OBJECTIVE: This study examines the benefit of physician profiling on cost and utilization of antibiotics. METHODS: General Practitioners, Family Practitioners, Internists and Pediatricians were sent an education tool regarding the appropriate use of antibiotics for the treatment of respiratory illnesses for the 2000-01, 2001-02 and 2002-03 seasons. Physicians who prescribed greater than 60 antibiotics in the previous year also received a profile of their first line antibiotic use. The average ingredient cost per prescription for profiled vs. non-profiled physicians was used to determine the impact of physician profiling on antibiotic prescribing behavior. Physicians were also surveyed during the 2000/01 season on the usefulness of the education tool and the profile. RESULTS: Approximately seventeen thousand physicians were targeted for each season. The ingredient cost per prescription for first line antibiotics was significantly lower for profiled (N = 3,286) vs. non profiled physicians in all three seasons: $5.19 vs. $5.31 (p <0.0001) for season 1; $6.29 vs. $6.57 (p <0.0001) for season 2; and $8.39 vs. $8.57 (p = 0.0003) for season 3. The ingredient cost per prescription was also lower for second line antibiotics in the profiled vs. non-profiled groups for each consecutive season: $55.35 vs. $67.09 (p = 0.057), $56.53 vs. $57.35 (p <0.0001), and $56.58 vs. $57.22 (p = 0.0001), respectively. Out of the 4.1% of physicians who responded to the program survey, 84% agreed that the information in the education tool was informative and useful. Seventy eight percent would consider the information when prescribing. Seventy-five percent of the profiled physicians who responded agreed that the profiles were informative and useful, and 67% would consider the information in their prescribing decisions. CONCLUSION: Providing antibiotic prescribing profiles for physicians may influence prescribing patterns and maintain cost in a managed care setting.