Purpose: The aim of this study is to investigate the relationship between the duration of clopidogrel use and the inflammation process after acute coronary syndrome in patients who received bare metal stent (BMS) or drug eluting stent (DES). Method: Sixty patients with acute coronary syndrome who received a stent were divided into three groups: 20 patients with BMS receiving clopidogrel for one month (BMS1 group), 20 patients with BMS receiving clopidogrel for 6 months (BMS6 group), and 20 patients with DES receiving clopidogrel for 6 months (DES group). High sensitive C-reactive protein (hsCRP, mg/dL) was measured at baseline, and then at first, third and sixth post-operative month. Results: The inital hsCRP levels were similar and decreased significantly in all groups by one month of clopidogrel treatment (from 7.1±1.9 to 3.8±2.3 in BMS1 group, p=0,002, from 6.5±2.8 to 4.3±2.5 in BMS6 group, p= 0,01 and from 7.7±2 to 3.6±2.4 in DES group, p