BACKGROUND The purpose of this study was to investigate the immediate effect of transcranial direct current stimulation (tDCS) on walking speed, functional strength of lower limbs, and balance in healthy older adults. Through this study, we intend to introduce a new method to improve the physical function of older adults. MATERIAL AND METHODS This was a randomized, controlled, double-blind study in which participants and evaluators were blinded. Among 57 healthy adults (aged 65 years or older), 31 underwent tDCS, while 26 received sham stimulation. For the pre-test, participants performed a 10-meter walk test, functional strength test of lower limbs, and static and dynamic balance tests. Next, the primary motor cortex area was subjected to tDCS for 20 min. Tests were repeated as post-tests. RESULTS There were significant differences in group-by-time interaction for 10-meter walk speed, functional strength of lower limbs, and static balance on the left side (P<0.05). There was not a significant group-by-time interaction for dynamic and static balance on the right side (P>0.05). There were significant differences in the main effect of time for 10-meter walk speed, functional strength of lower limbs, static balance on the right side, and dynamic balance (P<0.05). CONCLUSIONS Results showed tDCS was effective in improving gait and functional strength of the lower limbs in older adults. We recommend tDCS as a safe and effective way to improve motor performance and increase physical function, including walking and functional strength of lower limbs, in older adults.