Objective: To evaluate the influence of clopidogrel resistance on clinical outcomes of diabetic patients with acute myocardial infarction (AMI) received percutaneous coronary intervention. Methods: A total of 119 diabetic patients with AMI received percutaneous coronary intervention during Jan 2011 to Dec 2012 were enrolled in this study. All patients received standard antiplatelet therapy and platelet inhibition rate induced by adenosine diphosphate (ADP) was tested by thrombelastogram (TEG) after 24 h. According to ADP-induced platelet inhibition rate, the patients were classified into two groups: the study group (clopidogrel resistance group, ratio <50%, n=37) and the control group (ratio ≥50%, n=82). Clinic characteristics, biochemical indicator, death and major adverse cardiac events (MACE) during follow up were recorded. Results: The patients were followed up for a mean of (783±241) days. Clopidogrel resistance was detected in 37 patients (31%) and MACE occurred in 9 patients (7.6%). The incidence of MACE in one year were higher in the clopidogrel resistance group (16.2%) than in the control group (3.7%) (P=0.025). Clopidogrel resistance (P=0.334) was not associated with more than 1 year MACE. After multivariate analysis, clopidogrel resistance was not related with more than 1 year mortality. Conclusion: Clopidogrel resistance is common in the diabetic patients with AMI received percutaneous coronary intervention. Clopidogrel resistance indicates an increased risk of MACE in 1 year and is not associated with more long term (>1 year) prognosis of the patients.