Objectives: The obesity is a major risk factor for asthma, which is a serious and complex public health problem. The effect of obesity on exercise capacity in patients with asthma is unknown. Therefore, we aim to compare the exercise capacity between obese and non-obese patients who are diagnosed with asthma. Materials & Method: Forty-six male asthmatic patients participated in the study. The study used a crosssectional design; Participants were categorized into two groups, for comparison between 23 obese asthmatics (group A) and 23 non-obese asthmatics (group B). Height, weight, and level of physical activity questionnaire were obtained. Also, maximal oxygen consumption (VO2 max) value and cardiopulmonary responses were measured during incremental cycle exercise test. Results: VO2 max and Metabolic Equivalents (METS) were significantly higher in non-obese asthmatic patients compared to obese asthmatic patients (23 ± 7.5 vs. 17.6 ± 3.8, p<0.05) for VO2 max, and (6.48 ± 2.1 vs. 5.09 ± 1.00, p<0.05) for METS. No significant differences were observed in cardiopulmonary responses (Heart rates and Oxygen saturation). Conclusion: Obesity might have unfavorable effects on exercise capacity (VO2 max) in patients who are diagnosed with asthma. Obese asthmatics had reduced cardiopulmonary fitness compared with nonobese asthmatics, while the cardiopulmonary responses were similar in both groups.