Objectives: To evaluate the feasibility and the ability to recruit and retain children with severe traumatic brain injury or cerebral palsy, and their families, to a simple home-based exercise programme and to assess the immediate and short-term effects of such intervention on reducing impairment and improving function. Study design: Randomized clinical trial. Participants: Twenty children aged 7-13 years, with traumatic brain injury (N = 10) or cerebral palsy (N = 10) who were independent ambulators. Five children from each group were randomly assigned to a control group - regular daily activities, or to an experimental group - regular daily activities plus a home-based task-oriented exercise programme of sit-to-stand and step-up exercise, for six weeks. Outcome measures: Feasibility: The number of participants who completed the programme protocol. Efficacy: Timed Up and Go Test and Functional Reach Test were used as functional balance tests. Maximal isometric strength was assessed by using a hand-held dynamometer; walking performance was assessed by the 10 m walk test, 2-minute walk test and Energy Expenditure Index. Results: Nine children completed all parts of the training programme. At the end of the intervention period an increase of 3-4 cm in the mean Functional Reach Test and a reduction of 1.6 ± 2.1 seconds in the Timed Up and Go Test were noted (P<0.01) in the experimental group while no changes were noted in the control group. In all other outcomes assessed no significant differences were noted between groups. The positive change in balance performance in the experimental group was maintained during a six-week follow-up period. Conclusions: A home-based task-oriented exercise programme can improve balance performance in children with spastic cerebral palsy or severe traumatic brain injury.