Objectives. Poor endurance and early fatigue are factors contributing to ambulatory decline in cerebral palsy that was associated with lack of physical activity and secondary impairments. Therefore, this study aimed to investigate the effect of aerobic power training on walking efficiency and function in children with cerebral palsy. Methods. Thirty children with spastic cerebral palsy, of both sexes, aged between 6.41 to 16.8 years, were randomly allocated to either study or control group. Study group participated in aerobic power training with heart rate biofeedback for 30 minutes, 3 days per week, for 8 weeks in addition to a traditional physical therapy program, whereas control group received only traditional physical therapy program. Energy expenditure index (EEI) and its corresponding walking speed on a treadmill and gross motor function for standing and walking were measured pre- and post-treatment. Results. Comparing the results of pre- and post-treatment revealed that the measured variables were improved by statistically significant difference within both study and control groups, with a higher effect size and percentage of improvement in the study group. Post-training results revealed statistically non-significant differences between groups regarding the measured variables (EEI, TWS, GMFM-D, and GMFM-E). Conclusions. There was no statistical additional effect for the aerobic power training program. However, it was effective in improving walking efficiency and function in children with spastic cerebral palsy with higher percentage of improvement than the traditional physical therapy training program.