Objective: This study was conducted to understand how eating speed and oral health condition are associated with obesity in Japanese working men. Methods: We studied a total of 863 men attending an annual medical checkup of the Japanese Maritime Self Defense Force in Sasebo City, Japan. Participants answered a questionnaire about their eating speed, and we examined their anthropometric status in terms of BMI, waist circumference, and oral health condition, especially periodontal disease and number of functional teeth. Multivariate logistic regression analyses adjusting for potential confounding variables were performed. Results: The multivariate-adjusted odds ratio for waist circumference greater than 90 cm of the 'very fast' group compared to the 'slow, very slow' group was 5.22 (95% confidence interval 1.81-15.06) after adjusting for potential confounding factors. Individuals were more likely to have waist circumference greater than 90 cm if they had a larger 'number of missing functional teeth' (odds ratio 1.14
95% confidence interval 1.01-1.28) and severe periodontal disease (odds ratio 2.74
95% confidence interval, 1.46-5.13). Conclusion: Eating speed, the number of missing functional teeth, and severe periodontal disease are associated independently with larger waist circumference.