Objective: To investigate the influence of dentures wearing on the parameters of physical fitness, particularly on agility and balance function in elderly people. Design: A case control study. Setting: Motohachiohjimachi, Hachiohji, Tokyo, Japan. Methods: Motor reaction time was measured in the presence and absence of dentures in the subjects who were 1) in a sitting position and lifted the lower limbs as fast as possible in response to a stimulus (Sitting Group) and those who were 2) in a standing position and jumped upright as fast as possible in response to a light stimulus (Jumping Group). The effects of dentures wearing on balance function were investigated by comparing the measured values of static and dynamic body sway. Results and Conclusions: Light-reaction time was not significantly influenced by dentures wearing in Sitting Group performing a light body movement that required little muscular force. In a relatively heavy body movement that required agility (i.e., jumping from the standing position), the reactivity changed depending on the muscular force; which might result in the difference of the reactivity due to dentures wearing (i.e., t-test showed a significant difference in the light-reaction time under clenching posture between with and without wearing dentures (p<0.01)). No significant difference was observed in body sway under clenching posture between with and without wearing dentures. Therefore, we assumed that reaction speed varied depending upon dentures wearing.