Children with cerebral palsy (CP) often present with upper extremity (UE) function impairments that hamper physical and functional abilities necessary for daily activities of daily living (ADL) and participation at play and leisure activities in various environments. The traditional repetitive task practices (RTP) have proven helpful when therapists provide one-on-one therapy for long duration and with high repetitions. Unfortunately, compliance with such time-intensive therapy interventions is low. We have developed a low-cost computer game-assisted rehabilitation platform (GRP) based on RTP principles to provide fine and gross motor UE exercises for children with CP. The aim of this thesis was to determine the reliability and validity of the Computer games-assisted Upper Extremity (CUE) assessment tool and feasibility of conducting a full scale, multicenter randomized controlled trial (RCT) to evaluate the treatment effect of the RTP-based computer game-assisted rehabilitation platform (GRP) in improving upper limb function in 4 to 10-year-old children with CP. For understanding the feasibility, a mixed method exploratory randomized controlled trial was conducted. For assessing the test-retest reliability and convergent validity of the CUE assessment tool, thirty-five children with CP (age 4 to 10 years) were recruited. Assessments were performed two weeks apart. During the first assessment session, participants were assessed using the Quality of Upper Extremity Skills Test (QUEST) and Peabody Developmental Motor Score version-2 (PDMS-2) along with the CUE assessment tool. Data analysis showed moderate to high Intra Class Coefficient (ICC) scores with low to moderate Minimal Detectable Change (MDC) values, with excellent test-retest reliability. For the RCT, the experimental group received a forty-five minute GRP based therapy session three to five times a week for sixteen weeks. The control group received forty-five minute high repetitions of various task-based activities sessions three to five times a week for sixteen weeks. Pre- and post-intervention assessments were conducted using the QUEST, PDMS-2, and CUE assessment tool scores. Semi-structured interviews of parents were conducted at the end of the 16-week-long therapy protocol. The qualitative and quantitative data analysis results show that the GRP platform effectively improves object manipulation skills in children with hand and arm function impairments due to CP.