Objective: This study aimed at assessing how the addition of Nintendo Wii (NW) system to the traditional therapy influences occupational performance, balance, and daily living activities in children with spastic hemiplegic Cerebral Palsy (CP). Materials and Methods: The present study is a single-blind and randomized trial involving 24 children aged 6-14 years, classified as level I or II on the Gross Motor Function Classification System. The children were allocated into two groups: an intervention and a control group, and their families participated in the study. The activity performance analysis of the children was undertaken by using the Canadian Occupational Performance Measure (COPM), functional balance was measured with the Pediatric Balance Scale (PBS), and activities of daily living were assessed with Pediatric Evaluation of Disability Inventory (PEDI). Twenty-four children with CP were randomly divided into two groups: intervention (n=12) and control group (n=12). All children in both groups continued their traditional physiotherapy program twice a week, 45 minutes per session, whereas the participants in the intervention group, additionally, were trained with NW, two other days of the week for 12 weeks, with each session lasting for 30 minutes. Results: Self-care, mobility, PEDI total, PBS, and performance of COPM scores increased in the NW group after intervention. Self-care, mobility, and total PEDI increased in the control group as well. However, there was no statistically significant difference found between the groups, except for PBS (P<0.05). Conclusions: NW contributed to the implementation of occupational performance, daily living activities, and functional balance. We recommend that NW could be used in the rehabilitation program to engage play-based activities with fun.