[Purpose] We aimed to determine the effects of ventilation feedback using electrical stimulation on ventilation pattern during exercise in patients with chronic obstructive pulmonary disease (COPD), and develop new rehabilitation methods. [Subjects] This randomized double-blind placebo-controlled trial included 24 patients with COPD. [Methods] Phasic electrical stimulation during expiration (PESE) or a placebo was given to all the cases. Minute ventilation (VE), tidal volume (TV), respiratory rate (RR), expiratory time (Te), total respiratory time (Ttot), dead-space gas volume to tidal gas volume (VD/VT), oxygen uptake (VO₂), carbon dioxide output (VCO₂), Borg scale (Borg), and percutaneous oxygen saturation (SpO₂) during rest and exercise were assessed. [Results] The placebo group showed no obvious change in ventilation measurements at rest or during exercise. However, in the PESE group, TV, Te, and Ttot significantly increased, while RR and VD/VT significantly decreased during exercise compared with the baseline measurements. Borg scores, SpO₂, VO₂, or VCO₂ did not differ significantly. [Conclusion] PESE improves the ventilation pattern during rest and exercise. Furthermore, PESE does not increase VO₂, which may indicate an increased workload. Biofeedback may contribute to PESE effects. Stimulation applied during expiration may evoke sensations increasing prolonged expiration awareness, facilitating prolongation.