Many epidemiological studies have indicated that periodontitis is an important risk factor for coronary heart disease (CHD). We examined whether plasma antibody levels to 3 major periodontal pathogens, Aggregatibacter actinomycetemcomitans, Porphyromonas gingivalis, and Prevotella intermedia predicted the risk of CHD events. A nested case-control research design (case: n = 191, control: n = 382), by matching gender, age, study area, date of blood collection, and time since last meal at blood collection, was employed in a large cohort of Japanese community residents.Antibody levels of periodontopathic bacteria were associated with risk of CHD after adjusting for BMI, smoking status, alcohol intake, history of hypertension, history of diabetes mellitus, exercise during leisure time, and perceived mental stress. The association was different by age subgroup. For subjects aged 40-55 years, the medium (31.7-184.9 U/mL) or high tertile plasma antibody level (> 184.9 U/mL) of A. actinomycetemcomitans showed higher risk of CHD (medium: OR = 3.72; 95% CI = 1.20-11.56, high: OR = 4.64; 95% CI = 1.52-14.18) than the low tertile level (< 31.7 U/mL). The ORs of CHD incidence became higher with an increase in IgG level of A. actinomycetemcomitans (P for trend = 0.007). For subjects aged 56-69 years, the high tertile level (> 414.1 U/mL) of P. intermedia was associated with higher risk of CHD (OR = 2.65; 95% CI = 1.18-5.94) in a dose-response fashion (P for trend = 0.007). The possible role of periodontopathic bacteria as a risk factor for CHD incidence was suggested by the results of this study by the elevated antibody level to these bacteria with the increased risk of CHD.