Objective: The aim of this study is to investigate the role of activated protein C resistance (APCR) as a contributing factor in the pathogenesis of myocardial infarction.Methods: Forty patients with acute myocardial infarction (AMI) who have been followed by the Cardiology Department of Gülhane Military Medical Academy Haydarpaşa Training Hospital and 30 healthy individuals were included in this study. Patient group consisted of 27 males and 13 females, (mean age 47.9 (23-81) control group composed of 16 males and 14 females, (mean age 46.1 (24-63) Whole blood count and routine biochemical work up were performed and activated protein C resistance (APCR) ratio, and activated partial thromboplastin time were evaluated in both groups.Results: Two patients and three controls had APCR. Mean APCR ratio was 2.56 ± 0.56 in the control and 2.74 ± 0.67 in the patient group and there was no statistically significant difference between the two groups (p>0.05).Conclusion: Although APCR is a major risk factor for venous thrombosis, its role