Age-related changes in masticatory function were investigated in complete denture wearers. The sieving method using peanuts as a test food was compared with the result obtained using a food questionnaire for evaluation of masticatory function. In relationship to aging, both the masticatory performance and the chewing score decreased significantly (the masticatory performance: r = .60, P < .01; the mastication score: r = -.46, P < .05). It is suggested that the masticatory function in complete denture wearers decreases in relationship to aging. The food intake questionnaire is useful for evaluating masticatory function in complete denture wearers.