Purpose: The objective of this randomized single blind (outcome assessor) controlled trial was to evaluate the efficacy of 4weeks of modified constraint induced movement therapy (mCIMT) in improving upper limb function in 3–8years old children with hemiplegic cerebral palsy. Methods: Thirty-one children were randomly assigned to receive the mCIMT (N=16) with conventional therapy or conventional therapy alone (N=15). Children were evaluated three times (at enrollment, follow up at 4weeks and 12weeks). The primary outcome measure was difference in “change in mean total QUEST scores” at 4weeks of intervention between the intervention and the control arm. Results: After 4weeks of intervention, mCIMT group showed significant change in the affected upper limb in QUEST scores (10.7±5.2 vs 1.4±1.7, p<0.001) and time (s) to complete nine-hole-pegboard test compared with control group [60(0–130) vs 5(−12 to 30), p<0.001]. The improvement observed in upper limb function after 4weeks of intervention persisted 8weeks after discontinuation of intervention in mCIMT group. Conclusion: The modified constraint induced movement therapy appears to be effective in improving upper limb function in 3–8years old hemiplegic cerebral palsy children.