Background: Type 2 diabetes is a global public health crisis that threatens the economies of all nations, particularly developing countries^. Hyperprolactinemia may reflect neuroendocrine stress reaction to acute coronary syndromes, which induces acute endothelial dysfunction, insulin resistance, and induction of vascular immune reactions; thus, prolonged hyperprolactinemia lead to arteriosclerosis, augmentation of arterial stiffness, and hypertension. Objective: To assess role of prolactin as a cardiovascular risk in type 2 diabetes mellitus patients in Zagazig University Hospitals. Patients and Methods: This study was performed in Clinical Pathology, Cardiology and Internal Medicine Departments Zagazig University Hospitals in the period between July and October 2019. Approval for study was obtained from research administration and research ethics committee, Faculty of Medicine Zagazig University. Results: Regarding prolactin level, there was a statistically significant increase on comparing group 1 with group 2, 3 and 4 (P= 0.016, P<0.001, respectively). Also, there was a statistically significant increase on comparing group 2 with group 3 and 4 (p < 0.001), in addition to significant increase on comparing group 3 with 4 (p=0.012). In the present study, serum prolactin increased in patients with acute myocardial infarction (AMI) either in group1 (MI and DM) (mean=26±SD=8.09) or group 2(MI) (mean=16.24± SD =3.37), which points to the possible role of hyperprolactinemia in myocardial infarction. Prolactin was found to be increased as a marker of atherosclerosis so it can be used as biomarker for atherosclerosis or coronary artery disease. Conclusion: Prolactin can be used as biomarker for coronary artery disease and this is explained by its participation in the process of atherosclerosis. Serum prolactin level increased in acute myocardial infarction.