To evaluate the effect of stretching and progressive resistance exercise on range of motion and muscle strength in children with cerebral palsy. Thirty-seven children with spastic bilateral cerebral palsy and Gross Motor Function Classification System levels I to III were randomized to an intervention and a comparison group. The intervention included stretching of hamstrings and progressive resistance exercise, targeting the lower extremities for 16 weeks, followed by a 16-week maintenance program. Passive and active popliteal angle and muscle strength were evaluated at 0, 16, and 32 weeks. After 16 weeks nonsignificant improvements were found in passive, active popliteal angle and quadriceps and hamstrings strength. A 16-week stretching and progressive resistance exercise program followed by a 16-week maintenance program showed nonsignificant improvements in passive, active popliteal angle and muscle strength for the intervention group.