OBJECTIVES: The Essential Medicine Policy (EMP) was implemented to improve the affordability of medicines and reduce patients’ economic burden in 2009 along with the new round of health care reform in China. This study is to evaluate the effects of EMP on patients’ health care utilization and spending. METHODS: Urban Employee Basic Medical Insurance (UEBMI) claims of Tianjin city from April 2008 to March 2010 were used to compare the patients’ outpatient visit, total spending, drug spending, and OOP spending before and after the implementation of the EMP. The intervention group consisted of patients who visit the primary care institution which implemented EMP at least once before and after EMP and did not visit the control primary care institution which did not implement EMP, vice versa for the control group. A difference-in-difference approach was used to estimate the effects adjusting for patients’ socio-demographic characteristics and disease severity. Negative binomial regression was used to estimate the outpatient visit and tobit model was used to estimate the cost. RESULTS: Totally, 23362 patients from 49 interventional primary care institution and 4148 patients from 42 control institution were involved in the study. The regression results showed that the annual patients’ outpatient visits (0.5%, p=0.791) and the visits to primary care institution (0.2%, p=0.951) had no change after implementing EMP compared to the control group. The patient’s average total spending (-0.6%, p=0.850), drug spending (1.6%, p=0.703) and OOP spending (0.4%, p=0.883) did not change. The average total spending (2.9%, p=0.443), drug spending (1.9%, p=0.724) and OOP spending (1.2%, p=0.722) in primary care institution was also not changed after implementing EMP. CONCLUSIONS: The EMP in Tianjin China was not associated with more outpatient visits in primary care institution and less medical spending, drug spending and OOP spending.