We examined the effects of a 20-week intra-dialytic rehabilitation (ID-RHB) program on the physical performance and arterial stiffness in a group of patients undergoing regular ambulatory hemodialysis (14 men, 3 women; mean age: 45.4 ± 13.4 years; mean duration of dialysis: 5.9 ± 2.3 years). The patients underwent exercise aerobic training on programmable bed-side ergometers (letto2, RECK MOTOmed®, GmbH, Germany) 2-3 times weekly. Seventeen patients completed the 20 weeks of ID-RHB program. Five patients were excluded from the program for loss of motivation, 4 patients for repeated failure to fulfill the prescribed training regimen and 1 patient was transplanted. Twenty weeks of ID-RHB program led to significant increase of VO2peak (from 18.2 ± 5.8 to 19.7 ± 5.1 ml/ kg/min; P < 0.004); distance walked in 6 minutes (from 455.2 ± 98.2 to 526.7 m ± 139.6; P < 0.02); muscle strength (from 271.7 ± 87.6N to 336.7 ± 97.7N; 0.02). Mean CAVI value significantly decreased from the initial 8.02 ± 1.7 to 7.32 ± 1.9 (P < 0.02). The training protocol and workload intensity was well tolerated by all the subjects and there were no adverse events, such as episodes of hypotension, related to exercise. We conclude that structured intra-dialytic aerobic exercise training is safe and can improve the endurance parameters and arterial stiffness in HD patients.