AIM: To assess the impact of the National Essential Medicines Policy (NEMP) on the use of medicines in government-owned primary care institutions in Hubei province of China. STUDY DESIGN: Quasi-experimental design and time-trend analysis. METHODS: A systematic random sampling strategy was employed to select 55,800 prescriptions from 18 primary care organizations who progressively implemented the NEMP from January 2009 to July 2011. We examined the change of patterns of prescriptions. The facilities that implemented the NEMP at a later stage served as control. RESULTS: An immediate increased uptake of essential medicines of all drugs prescribed which ultimately neared 95%. In total, 38,151 prescriptions (68%) involved antibiotics, and we found no evidence of reduction after the NEMP interventions. A high percentage (59-66%) of prescription drugs were administered through parenteral routes and no reduction was found after the NEMP interventions. Although the average number of medicines per prescription remained unchanged (nearly four), the average cost per prescription declined significantly after the NEMP interventions (¥ 44.67 vs ¥ 26.67 CNY, P < 0.03). CONCLUSIONS: The NEMP interventions reduced the average cost per prescription; however, the irrational use of antibiotics and unnecessary parenteral administration remains prevalent. The goals of the NEMP are partially achieved; we therefore recommend a strategic approach involving all stakeholders to comprehensively achieve all aspirations.