This pilot study was designed to examine the effects of short-term (48-hr) upper extremity inhibitive casting, with an encased thermoplastic splint, on problems related to upper motor neuron damage. The subject was an 8 1/2-year-old girl with left upper extremity spasticity. Three different measures were used: (a) rating of videotaped active movements of the child; (b) the Modified Ashworth Scale, a clinical measure of spasticity; and (c) The Biodex System, a measure of torque during passive elbow flexion and extension. After cast removal, subjective improvements were noted in the quality of active movement (through videotapes) and increased awareness and use of the casted hand by the child (through parents' reports). A trend toward decreased spasticity was demonstrated by the Modified Ashworth Scale and a statistically significant decrease in resistance to passive movement was shown by the Biodex recordings. However, this reduction in symptoms was temporary, lasting less than 3 days. The results of this study suggest that short-term inhibitory casting may prove efficacious in the treatment of the child with cerebral palsy, although further research is needed.