We assessed the effectiveness of an educational intervention in reducing antibiotic prescribing in public primary care clinics in Malaysia. Twentynine medical officers in nine clinics received an educational intervention consisting of academic detailing from the resident Family Medicine Specialist, as well as an information leaflet. The antibiotic prescribing rates were assessed for six months - three months before and three months after the intervention. A total of 28, 562 prescriptions were analyzed. Among participating doctors, general antibiotic prescribing rates for pre- and post-intervention phases were 14.3% and 11.0% (post-intervention vs preintervention RR 0.77, 95% CI 0.72 to 0.83). The URTI-specific antibiotic prescribing rates for pre- and post-intervention phases were 27.7% and 16.6%, respectively (post-intervention vs pre-intervention RR 0.60, 95% CI 0.54 to 0.66). No significant change in antibiotic prescribing rates was observed among primary care practitioners who did not participate in the study. This low cost educational intervention using both active and passive strategies focusing on URTI produced a statistically significant (and clinically important) reduction in antibiotic prescribing.