PURPOSE: The proportion of elderly people in Japan’s population now exceeds 28%, identifying the country as a “super-aging society.” It is important for people to maintain health and independence as they age. Therefore, it is important for them to maintain functional fitness. The purpose of this study was to analyze the associations between accelerometer-determined physical activity and clinical measures of functional fitness. METHODS: One hundred ninety-nine community-dwelling Japanese women (age: 68.9 ± 4.8 years, BMI: 22.4 ± 2.8) wore an Active Style Pro HJA-350IT accelerometer for five weeks (Omron Healthcare Co., Ltd, Japan) on their waistline for the entire day, except when bathing, showering, swimming, or sleeping. The instrument measured the daily number of steps and accumulated time (minutes) spent in sedentary behavior (SB: < 1.5 metabolic equivalents or METs; 1 MET=3.5 ml/kg/min), light-intensity physical activity (LPA: 1.5 to 2.9 METs), and moderate- and vigorous-intensity physical activity (MVPA: ≥ 3.0 METs). Common functional fitness measures included hand grip, sit-up, sit and reach, functional reach, chair stands, 10-m walk, 10-m obstacle walk, and timed up and go. Functional fitness of participants was compared according to quartiles of steps/day and time spent in SB, LPA, and MVPA. These quartiles are denoted as Q1 (lowest activity quartile), Q2, Q3, and Q4 (highest activity quartile). RESULTS: Participants accumulated (median, [IQR]) 6,939 [5,000-8,896] steps/day, 286.1 [228.0-349.7] SB min/day, 451.1 [398.1-509.3] LPA min/day, and 68.9 [45.7-93.0] MVPA min/day. The 10-m walk, 10-m obstacle walk, and timed up and go measures differed significantly across the steps/day quartiles (Q1<Q2, p<0.05) and MVPA quartiles (Q1<Q2, Q3, Q4, p<0.05). The 10-m walk (Q1<Q2, p<0.05), timed up and go (Q1<Q2, p<0.05), and functional reach (Q2, Q3> Q4, p<0.05) measures differed significantly across SB quartiles. There were no differences observed across LPA quartiles. CONCLUSIONS: Accelerometer-determined physical activity, especially time in MVPA, was associated with a number of different functional fitness measures.