Materials & Methods: In this pretest - posttest quasi experimental study, 20 cerebral palsy hemiplegic children 6 to 12 years old (15 boys and 5 girls) with  8.7   years mean age were selected. Interventions were performed about 8 weeks and patients were followed for 4 weeks. Spasticity on the affected side in wrist and elbow were tested by Modified Ashworth Scale and upper extremity function by the Box & Block test. The data were analyzed with the Wilcoxon and paired t- tests.

Results: Constraint-Induced Therapy in the affected limb decreases significantly the spasticity of wrist (p = 0.00) and elbow (p = 0.005) and significantly increases performance score (p = 0.00), and the recovery significantly maintained one month after the interventions.

 conclusion: Constraint-Induced Therapy of affected upper extremity could possibly decrease limb spasticity and increase function with two mechanisms: Fierstly, The reduction of not using the plegic side and secondly, neuroplasticity in CNS. This improvement may remain viable in the affected limb.