The quality of physician prescribing is suboptimal. Patients are at risk of potentially adverse reaction because of inappropriate or writing error in the drug prescriptions. We assess the effect of “group academic detailing” to reduce writing drug name using brand name and short form in the drug prescriptions in a controlled study at two primary health care clinics in Negeri Sembilan. Five medical officers in Ampangan Health Clinic received an educational intervention consisting of group academic detailing from the resident Family Medicine Specialist, as well as a drug summary list using generic names. The academic detailing focused on appropriate prescribing habit and emphasized on using the full generic drug name when writing the drug prescription. Analyses were based on 3371 prescriptions that were taken from two clinics. The other health clinic was for comparison. The prescribing rates were assessed by reviewing the prescriptions (two months each for pre- and post-intervention phase). Statistically significant reduction in writing prescription using brand name and using short form were observed after the educational intervention. Writing prescription using brand name for pre- and post-intervention phase were 33.9% and 19.0% (postintervention vs pre-intervention RR 0.56, 95% CI 0.48 to 0.66) in the intervention clinic. Prescription writing using any short form for pre- and post-intervention phase were 49.2% and 29.2% (post-intervention vs pre-intervention RR 0.59, 95% CI 0.53 to 0.67). This low cost educational intervention focusing on prescribing habit produced an important reduction in writing prescription using brand name and short form. Group detailing appears to be feasible in the public health care system in Malaysia and possibly can be used for other prescribing issues in primary care.