📘 The development of an independent and efficient walking is one of the major targets for children with cerebral palsy especially those with spastic diplegic type of cerebral palsy. The purpose of this study was to compare the efficacy of unweighing system during treadmill versus over ground walking on gait pattern in children with spastic diplegia. Sixty children with spastic diplegia from both sexes with mean age 7.4 years participated in this study. They were classified into three groups of equal number, (one control and two study groups). Gait pattern was assessed using the Biodex Gait Trainer II and Gross Motor Function Measure (GMFM) for all groups before and after three months of the application of the treatment program. The results of this study revealed statistically significant improvement (P<0.05) in the measured variables ((walking speed, step length, time on each foot and GMFM score) for both study groups in favor to first study group. Therefore it's better to uses the unweighing system with over ground walking as an additional therapeutic modality to improve gait pattern and functional abilities of diplegic children.