Objective To evaluate the effect of quadriceps functional electrical stimulation (FES)-cycling on exertional oxygen uptake (Math Eqo2) compared with placebo FES-cycling in patients with chronic obstructive pulmonary disease (COPD). Design A randomized, single-blind, placebo-controlled crossover trial. Setting Pulmonary rehabilitation department. Participants Consecutive patients (N=23) with COPD Global Initiative for Chronic Obstructive Lung Disease stage 2, 3, or 4 (mean forced expiratory volume during the first second, 1.4±0.4L [50.3% predicted]) who had recently begun a respiratory rehabilitation program. Intervention Two consecutive 30-minute sessions were carried out at a constant load with active and placebo FES-cycling. Main Outcome Measures The primary outcome was mean Math Eqo2 during the 30-minute exercise session. The secondary outcomes were respiratory gas exchange and hemodynamic parameters averaged over the 30-minute endurance session. Lactate values, dyspnea, and perceived muscle fatigue were evaluated at the end of the sessions. Results FES-cycling increased the physiological response more than the placebo, with a greater Math Eqo2 achieved of 36.6mL/min (95% confidence interval [CI], 8.9–64.3mL/min) (P=.01). There was also a greater increase in lactate after FES-cycling (+1.5mmol/L [95% CI, .05–2.9mmol/L]; P=.01). FES-cycling did not change dyspnea or muscle fatigue compared with the placebo condition. Conclusions FES-cycling effectively increased exercise intensity in patients with COPD. Further studies should evaluate longer-term FES-cycling rehabilitation programs.