This study aimed to explore the relationship between oral and cognitive functions in community-dwelling older adults who underwent dental and oral health examinations and health check-ups conducted by the Shimane Extended Union of the Medical Care System for Latter-Stage Elderly People between April 2020 and March 2022. Data on general background, oral health status, and cognitive function were collected. Logistic regression analysis was performed as the primary analysis with cognitive function as the objective variable. The participants included 4,338 cases, excluding 1,757 with missing data. The analysis of forgetfulness revealed significant correlations with age, sex, lower leg circumference, masticatory function, swallowing function, oral hygiene status, current smoking status, social participation, and orthopedic disease. Significant correlations were found between age, lower leg circumference, oral dryness, social participation, stroke, and orthopedic disease (p < 0.05). Cognitive function may be associated with declines in oral function and hygiene status in community- dwelling older adults.