Objective: Motor function in children with Down syndrome is similar to mentally retarded children. But the movements are slower and have lower quality. The purpose of this study was to identify weaknesses in motor function in children with Down syndrome, by using Bruininks Oseretsky Test of Motor Proficiency (BOTMP).

Materials & Methods: In this cross-sectional study, thirty six children with intellectual disability, 18 girls with Down syndrome and 18 girls without Down syndrome, with chronological aged 8-13 years were investigated. The subjects of Down syndrome were selected by available sampling. The subjects of intellectual disability were selected by simple random sampling. Two groups of participants were matched for chronological age and IQ level. The measurement was BOTMP. Statistical analysis was performed using the Mann-Whitney U rank sum test and t-test.

Results: The children with Down syndrome scored significantly lower than the mentally retarded children in the areas of gross motor skill composite (P<0.014) balance (P<0.029), response time (P<0.034) and visual motor control (P<0.048), but the fine motor and overlay motor skill composite, and subtests of bilateral coordination, strength, upper limb coordination scores were no significantly different between two groups.

Conclusion: Motor rehabilitation is appropriate for children with intellectual disability, especially for children with Down syndrome, in throughout their adolescence. Key words: Motor skill/ Intellectual Disability/ Down syndrome/ BOTMP