One of the most prevalent illnesses in developing countries is myocardial infarction (MI), which develops when the heart's blood supply is suddenly interrupted and causes tissue damage. It is connected to several metabolic risk factors, including diabetes, hypertension, and obesity. The objective of this study was to assess how oxidative stress (OS) contributed to the pathophysiology of MI and T2DM. The current study examined 152 male samples, including 52 MI patients without T2DM (G1), 50 MI patients with T2DM (G2), and 50 seemingly healthy men as controls (C). The levels of fasting blood sugar (FBS), C-reactive protein (CRP), total oxidant status (TOS), total antioxidant status (TAS), oxidative stress index (OSI), malondialdehyde (MDA), and total peroxidase activity were assessed. Based on the results, CRP levels increased significantly in both the G1 and G2 groups compared to the C group, with G2 reporting greater significant increases than G1. Both the G1 and G2 groups considerably exceeded the C group in terms of TOS, OSI, MDA, and total peroxidase activity. In contrast to the C group, the TAS was found to be much lower in the G1 and G2 groups. Additionally, there were no noticeable variations in the TOS, TAS, OSI, MDA, or total peroxidase activity between the G1 and G2 groups. According to our findings, individuals with MI and T2DM had an increased OS and a diminished antioxidant system. Consequently, OS may be crucial to the pathophysiology and prognosis of MI and T2DM.