OBJECTIVE: The ramp exercise test has been widely used to evaluate cardiopulmonary responses to an incremental exercise load. This study was performed to clarify whether different slopes of the ramp exercise test influence exercise tolerance, exercise limiting factors, and respiratory pattern in patients with chronic obstructive pulmonary disease (COPD). SUBJECTS AND METHODS: We applied three different slopes (5 W/min, 10 W/min and 20 W/min) of the ramp exercise test in 9 patients with COPD and evaluated cardiopulmonary responses. RESULTS: There were no significant differences in peak oxygen uptake, anaerobic threshold (AT), minute ventilation, heart rate, arterial oxygen saturation, expired tidal volume, or respiratory rate at the maximal load among the three different ramp exercises tested. AT could be determined in six of nine patients (67%) at the slope of 5 W/min, in 8/9 (89%) at the slope of 10 W/min, and in 9/9 (100%) at the slope of 20 W/min. CONCLUSION: The findings suggest that the ramp slope does not affect exercise tolerance, exercise limiting factors, or respiratory patterns and each of these ramp slopes is useful for the evaluation of COPD. Ramp slopes of 10 W/ min or 20 W/min should be appropriate for the determination of AT.