Protein C is one of the most important factors that prevent blood from clotting. Protein C deficiency usually leads to venous thrombosis. We intend to report a male of 38 years admitted in coronary care unit of Dhaka Medical College Hospital, who suffered recurrent episodes of myocardial infarction, whose traditional risk factors were well controlled. Ultimately he was diagnosed with protein C deficiency, which is not commonly implicated in arterial thrombosis. Protein C deficiency can rarely cause severe life threatening arterial thrombosis, like myocardial infarction. Many more cases are reported in recent literature. It can happen sporadically. A high degree of suspicion should be maintained if traditional risk factors are absent in instances of arterial thrombosis, to look for protein C deficiency.