Periodontitis (PD) is a risk factor for acute myocardial infarction (AMI). C-reactive protein (CRP) is elevated in PD. The aim of this study was to investigate biochemical alterations among AMI with PD. Thirty non-AMI (25 non-PD and only 5 PD) and 30 AMI (13 PD and 17 non-PD) patients were participated. Serum CRP, tumor necrosis factor alpha (TNF-α), total cholesterol, low-density lipoprotein cholesterol, protein carbonyl (PC) contents, soluble vascular cell adhesion molecule-1 (sVCAM-1), adiponectin, creatine kinase, resistin, catalase and superoxide dismutase (SOD) levels were measured. AMI-PD elicited significant differences in percentage hypertension, diabetes, serum creatine kinase, cholesterol and low-density lipoprotein cholesterol. CRP among AMI-PD and non-AMI-PD was increased by 73.4% and 31.3%, respectively. The level of PC contents was increased significantly among AMI-PD and non-AMI-PD by 47.62% and 33.3%, respectively. Catalase and SOD levels were significantly decreased in AMI-PD by 33.7% and 34.1%, respectively; however, their levels among non-AMI-PD were significantly increased by 35.7% and 28%, respectively. TNF-α, sVCAM-1 and resistin levels among AMI-PD were increased by 134.3%, 68.8% and 25.5%, respectively; however, TNF-α and sVCAM-1 levels among non-AMI-PD were increased significantly by 21.4% and 29.4%, respectively. Adiponectin level produced insignificant changes. PD prevalence among AMI associated with elevated serum CRP, PC contents, sVCAM-1, TNF-α and resistin levels concurrent with declines in SOD and catalase enzymes. In conclusion, among nondiabetic, nonsmoking patients suffering from AMI, PD is highly prevalent and associated with elevated serum CRP, PC contents, sVCAM-1, TNF-α and resistin levels, associated with significant declines in antioxidant enzymes with insignificant change in serum adiponectin level.