PURPOSE: The association between periodontal disease and carotid atherosclerosis has been widely discussed, but to our knowledge, no population-based studies have been conducted on the association between masticatory ability and carotid atherosclerosis. We aimed to clarify the hypothesis that objectively accessed masticatory performance is related to increased intima-media thickness (IMT) in a general urban population. METHODS: We studied 1,484 Japanese (mean age: 66.9 y) from the Suita study. Masticatory performance was measured using test gummy jelly, and periodontal status was evaluated using the Community Periodontal Index (CPI). Carotid ultrasonography was performed to measure maximum IMT (max-IMT) in the entire area of the carotid arteries. Analysis of covariance was used to compare max-IMT according to quartiles of masticatory performance adjusted by cardiovascular risk factors and periodontal status. RESULTS: Multivariable-adjusted max-IMT (standard error) was significantly higher in the lowest masticatory performance quartile group (decreased group) (1.58 ± 0.03 and 1.44 ± 0.03 mm) than in the 2nd to 4th quartiles combined (non-decreased groups) in both sexes (1.48 ± 0.02 mm, trend P = 0.038) and in women (1.34 ± 0.02 mm, trend P = 0.013), respectively. In participants without cardiovascular risk factors (n = 250), multivariable-adjusted max-IMT was significantly higher in the decreased (1.54 ± 0.06, 2.08 ± 0.22, and 1.42 ± 0.06 mm) than in the non-decreased groups in both sexes (1.31 ± 0.04 mm, trend P = 0.006), in men (1.41 ± 0.12 mm, trend P = 0.028), and in women (1.28 ± 0.04 mm, trend P = 0.073). CONCLUSIONS: These findings suggest that decreased masticatory performance may be related to carotid IMT progression in the general urban Japanese population.