Background: Cerebral palsy (CP) is a non-progressive neuromotor disorder affecting movement, muscle tone, and posture due to brain injury during early development. Effective interventions are essential for improving functional outcomes in children with spastic diplegic CP.Objective: This study aimed to evaluate the effects of Rood's Ontogenic Motor Patterns (ROMP) on trunk control and balance in children with spastic diplegic cerebral palsy.Methods: A single-blinded randomized clinical trial was conducted with 22 children aged 3-10 years, diagnosed with spastic diplegic CP. Participants were randomly assigned to two groups: Group A received Functional Electrical Stimulation with ROMP, and Group B received conventional physical therapy. The intervention lasted five weeks, with three sessions per week. Outcomes were assessed using the Modified Ashworth Scale, Gross Motor Function Measurement Scale (GMFM-88), and Pediatric Berg Balance Scale. Data were analyzed using SPSS 27.Results: Group A showed significant improvement in balance (PBBS: pre 13.81 ± 1.64, post 24.18 ± 4.67; p=0.017) and GMFM-88 scores (pre 9.95 ± 109.50, post 15.73 ± 173.0; p<0.001). Spasticity reduced significantly in the ROMP group (MAS: pre 11.50 ± 126.50, post 7.30 ± 73.00; p=0.010).Conclusion: ROMP significantly improved balance and reduced spasticity in children with spastic diplegic CP compared to conventional therapy, suggesting its potential integration into rehabilitation programs.