Malondialdehyde (MAA) within a lipid pathway has been demonstrated to possess an important role in endothelial function that undergoes periodontitis and coronary heart disease (CHD) development. This study evaluated the impact of periodontitis, CHD, or a combination of both diseases (periodontitis + CHD) on salivary and serum MAA levels. The periodontal and clinical characteristics, serum, and saliva samples were collected from 32 healthy subjects, 34 patients with periodontitis, 33 patients with CHD, and 34 patients with periodontitis and CHD. Lipid profile and levels of MDA and C-reactive protein (CRP) were assessed. Patients in the periodontitis group (serum: 3.92 (3.7&ndash / 4.4) µ / mol/L / salivary 1.81 (1&ndash / 2.1) µ / mol/g protein, p < / 0.01) and in the periodontitis + CHD (serum: 4.34 (3.7&ndash / 4.8) µ / mol/L / salivary 1.96 (1.7&ndash / 2.3) µ / mol/g protein, p < / 0.001) group presented higher median concentrations of salivary and serum MAA compared to patients in the CHD (serum: 3.72 (3.5&ndash / 4.1) µ / mol/L / salivary 1.59 (0.9&ndash / 1.8) µ / mol/g protein, p < / 0.01) and control group (serum: 3.14 (2.8&ndash / 3.7) µ / mol/L / salivary 1.41 (0.8&ndash / 1.6) µ / mol/g protein, p < / 0.01). In univariate models, periodontitis (p = 0.034), CHD (p < / 0.001), and CRP (p < / 0.001) were significantly associated with MAA. In the multivariate model, only CRP remained a significant predictor of serum and salivary MAA (p < / 0.001) MAA levels. Patients with periodontitis and with periodontitis + CHD presented higher levels of salivary and serum MAA compared to healthy subjects and CHD patients. CRP has been found to be a significant predictor of increased salivary and serum MAA levels.