Thumb adduction is an abnormal pattern typically noted in children with spastic cerebral palsy. This abnormal pattern can limit hand function, specifically in the type and quality of prehension pattern used and in the coordination of release. This ABAB single-subject research was designed to examine the effects of short thumb opponens splint on hand function in cerebral palsy. The subject was a 4 years and 8 months old boy with right upper extremity spasticity. The child was fitted with a short thumb opponens splint, which was worn for 8 hours per day during the daytime. Two different measures were used: (a) prehension component scores; (b) Bruininks-Oseretsky test of motor proficiency. Data was collected three times a week for 10 weeks. Visual analysis of data indicate that after the application of a short thumb opponens splint, improvements were noted in the prehension pattern and fine motor functional task. The results of this study suggest that short thumb opponens splint may prove efficaciousness in the treatment of the child with cerebral palsy.