This study aimed to examine the effectiveness of mirror therapy on recovery in the severely impaired arm after stroke. DESIGN: Using single-blind randomized controlled design, patients with severely impaired arm within 1-month post-stroke were assigned to receive mirror therapy (n = 20) or control therapy (n = 21), 30 mins twice daily for 4 wks in addition to conventional rehabilitation. During mirror therapy and control therapy, subjects practiced similar structured exercises in both arms, except that mirror reflection of the unaffected arm was the visual feedback for mirror therapy, but mirror was absent for control therapy so that subjects could watch both arms in exercise. Fugl-Meyer Assessment and Wolf Motor Function Test were the outcome measurements. RESULTS: After the intervention, both mirror therapy and control therapy groups had significant arm recovery similarly in Fugl-Meyer Assessment (P = 0.867), Wolf Motor Function Test-Time (P = 0.947) and Wolf Motor Function Test-Functional Ability Scale (P = 0.676). CONCLUSION: Mirror therapy or control therapy, which involved exercises concurrently for the paretic and unaffected arms during subacute stroke, promoted similar motor recovery in the severely impaired arm.