Background: Conventional exercise training (ET) for elderly patients with heart failure (HF) includes low-intensity stretching and gait training. The effects of 2 types of low-intensity ET - machine-assisted cycling and conventional ET - on exercise capacity and endothelial function of elderly patients with HF was investigated in the present study. Methods and Results: Twenty-seven elderly patients with HF (mean age: 79.5 years) were randomly assigned to either a machine-assisted cycling group or a conventional ET group. At baseline and after 2 weeks of ET, all patients were tested for 6-minute walk distance (6MWD) and digital reactive hyperemia-peripheral arterial tonometry (RH-PAT). After 2 weeks of ET, a significant increase in 6MWD was observed in both groups with no significant difference between the groups. RH-PAT index significantly increased in patients aged 80 (1.55 +/- 0.33 to 1.93 +/- 0.62, P=0.035) and a trend toward increase in RH-PAT index in the machine-assisted cycling group was observed (1.59 +/- 0.52 to 1.93 +/- 0.63, P=0.053), although no change was observed in the conventional ET group. In the multivariate model, patients' age and machine-assisted cycling were associated with the increases in RH-PAT index (P<0.05). Conclusions: Machine-assisted cycling appeared to be as effective as conventional ET on exercise capacity in elderly patients with HF. Additionally, machine-assisted cycling has the potential to improve endothelial function in these patients. (Circ J 2012; 76: 1889-1894)