Background: Assessment of core stability (CS) in subjects with high body mass index (BMI) is critical for prognosis and for designing a core stabilization program. Objectives: Investigation the effect of BMI on core stability in healthy adults, and to compare the outcome between female and male healthy adults. Subjects: 90 healthy students with the right dominant lower limb admitted in this study based on the inclusion criteria, with the age of 19 to 25 years. Subjects have been distributed into three groups; Group I: 30 individuals with BMI<25 kg/m2. Group II: 30 individuals with BMI =25–30kg/m2. For group III: 30 individuals of BMI>30 kg/m2. 15 male and 15 female students were involved in each group. Material and Methods: Electronic scale of weight and stadiometer device: calculation of BMI percentage. Prokin system: to measure the motor control of CS by balance tests (static& dynamic). Results: There were significant differences in MLSD, AFBS, AMLS, and PE parameters of bilateral open and close eye static balance test in group III than other groups (p=<0.05). Also; COPX of right foot static balance test increased significantly in subjects of group III. Male subjects showed a significant increase in bilateral and unilateral static balance tests than females in group I&II, and in all groups for dynamic balance. Conclusion: The effect of BMI on CS is significant, and this could be used for preventive programs to improve motor performance.