Previous studies have shown conflicting results as to whether periodontitis (PD) is associated with increased risk of coronary heart disease (CHD). The aim of the current study was to evaluate whether such an association exists. A systematic review of the literature revealed 5 prospective cohort studies (follow-up >6 years), 5 case-control studies, and 5 cross-sectional studies that were eligible for meta-analysis. Individual studies were adjusted for confounding factors such as age, sex, diabetes mellitus, and smoking. The 3 study categories were analyzed separately. Heterogeneity of the studies was assessed by Cochran Q test. The studies were homogeneous; therefore, the Mantel-Haenszel fixed-effect model was used to compute common relative risk and odds ratio (OR). Meta-analysis of the 5 prospective cohort studies (86092 patients) indicated that individuals with PD had a 1.14 times higher risk of developing CHD than the controls (relative risk 1.14, 95% CI 1.074-1.213, P < .001). The case-control studies (1423 patients) showed an even greater risk of developing CHD (OR 2.22, 95% CI 1.59-3.117, P < .001). The prevalence of CHD in the cross-sectional studies (17724 patients) was significantly greater among individuals with PD than in those without PD (OR 1.59, 95% CI 1.329-1.907, P < .001). When the relationship between number of teeth and incidence of CHD was analyzed, cohort studies showed 1.24 times increased risk (95% CI 1.14-1.36, P < .0001) of development of CHD in patients with <10 teeth. This meta-analysis indicates that both the prevalence and incidence of CHD are significantly increased in PD. Therefore, PD may be a risk factor for CHD. Prospective studies are required to prove this assumption and evaluate risk reduction with the treatment of PD.