 The developed cashew apple juice based functional drink showed antioxidant and acetylcholinesterase suppression activities. Therefore, it was used for the investigation the effect of 12- week consumption of cashew apple juice on physical and psychological fitness of the middle aged and elderly volunteers. In this study, the healthy middle aged and elderly volunteers who were recruited to participate in this study were divided in to various groups consisting of placebo and the Cashew drink treated groups at doses of 120 and 240 mgday. All subjects had to consume the assigned drinks for 12 weeks. They were determined the parameters related to physical and psychological fitness before treatment and every 4 weeks throughout the study period. The assessments were also performed at 4 week after the cessation of cashew apple juice based drink consumption. The physical fitness assessment was performed via the battery test consisting of various tests including 30-second chair stand test which measured the muscle strength of the lower extremities, hand grip strength test which measured the muscle strength of hand, 6-minute walk test which measured cardio-pulmonary endurance and Tandem test which measured postural balance. The alteration of oxidative stress markers including the malondialdehyde level and the activities of superoxide dismutase SOD, catalase CAT and glutathione peroxidase GSH-Px in blood was also motored. The results showed that the volunteers who consumed cashew apple juice based drink at dose of 240 mgday improved the performance in 30-second chair stand test and 6-minute walk test at 12 weeks of consumption period. The enhanced GSH-Px activity and the decreased MDA level were also observed. Therefore, the data obtained from this study demonstrated the increased muscle strength of the lower extremities and the cardio-pulmonary endurance of the middle-aged and elderly volunteers. The possible underlying mechanism might occur partly via the improved oxidative stress status. 