Objective: To evaluate the role of an aerobic physical training program on psychosocial characteristics, quality of life, symptoms and exhaled nitric oxide of adults with moderate or severe persistent asthma. Methods: Twenty patients were randomly assigned to a Control Group (CG, n= 10, education program and respiratory exercises) and a Trained Group (TG, n= 10, education program and respiratory exercises plus aerobic training at 70% of the maximum power obtained). The intervention took place twice a week for three months. Maximum aerobic capacity, pulmonary function, effort dyspnea, anxiety levels, depression levels and quality of life were assessed before and after the treatment. Exhaled nitric oxide at rest and the number of days without asthma symptoms were evaluated every month. Results: The TG presented increased numbers of symptom-free days (TG 24.8 days [95%CI= 23-27] versus CG 15.7 days [95%CI= 9-21]; p< 0.05), decreased exhaled nitric oxide levels (TG 25.8 ppb [95%CI= 15.3-44.0] versus CG 44.3 ppb [95%CI= 24-60]; p< 0.05), decreased anxiety scores (TG 39.3 [95%CI= 37-50] versus CG 40.9 [95%CI= 37-50]; p< 0.001), decreased depression scores (TG 6.6 [95%CI= 1-21] versus CG 9 [95%CI= 1-20]; p< 0.001), improved quality of life (TG 42.8% [95%CI= 34.3-71.7] versus CG 69.6% [95%CI= 45.1-87.9]; p< 0.001) and improved aerobic aptitude (TG 25.7 mL/kg/min [95%CI= 6.2-31.3] versus CG 20.5 mL/kg/min [95%CI= 17.3-24.1]; p< 0.001). Conclusions: Our results suggest that physical training reduces exhaled nitric oxide and symptoms and improves the quality of life and psychosocial characteristics of adults with moderate or severe persistent asthma.