Aim To examine the effect of implantation of intracoronary stents on the serum levels of C-creative protein (CRP). Methods This study included 105 patients who underwent implantation of intracoronary stents and 242 patients who received coronary angiography (CAG). Serum CRP was measured in the early morning before the procedure and the following morning after the procedure. Results In patients with implantation of stents, CRP levels after the procedure were significantly higher than that before procedure (6.7±0.5 vs 17.6±1.0, p<0.01). In CAG group, however, CRP levels after angiography were not significantly higher than that before angiography (3.5±0.7 vs 3.6±0.8, p>0.05). Conclusions Implantation of intracoronary stents leads to a detectable increase in serum levels of CRP, which is probably related with plaque rupture, the intrinsic inflammatory or tissue damage within arterial intima treated with stents implantation. It is suspected that increased-CRP may be a manifestation of acute coronary syndrome.