The in-stent thrombosis is considered as a serious complication of percutaneous coronary intervention. The impaired response to the antiplatelet therapy may play an important role in this crucial problem. Recurrent thrombosis can be explained by genetic background. Because the phenomenon of clopidogrel resistance is associated with an increased risk of recurrent cardiovascular events, genetic variants of a platelet receptor P2Y(12) might be the risk factor. Although there is no test recommended to assess the response to the antiplatelet therapy, the presented case suggests platelet function analysis should be undertaken in patients with recurrent stent thrombosis.