Previous reports have shown the benefits of intradialytic exercise to patients undergoing hemodialysis. However, most of those studies assessed the effects of exercise in middle-aged patients and little is known about advanced-age patients undergoing hemodialysis. Therefore, the present randomized controlled trial was performed to determine the effectiveness of exercise therapy in advanced-age patients undergoing hemodialysis. This non-blinded, randomized controlled parallel trial enrolled a total of 101 patients who were randomly assigned to intradialytic exercise (n = 51) or usual care (n = 50) groups. The training program included both resistance and aerobic exercises and was performed three times per week for 6 months. The aerobic exercise intensity was adjusted to a target Borg score of 13 for 20 minutes. Four types of resistance exercises were performed using elastic tubing, with three sets of 10 exercises performed at moderate intensity (13/20 on the Borg scale). The usual care group received standard care. Lower extremity muscle strength, Short Physical Performance Battery score, and 10-m walking speed were the outcomes and were evaluated before the hemodialysis session and after 6 months of training. There were statistically significant improvements in Short Physical Performance Battery score (effect size, 0.57; 95% confidence interval, 0.15‒1.95) in the exercise group relative to the control group. There were no statistically significant differences in lower extremity muscle strength or in the 10-m walking speed between the two groups. These findings suggest that 6 months of intradialytic training could improve physical function in older patients undergoing hemodialysis.