The purpose of this study was to compare and evaluate various hand functions in the most common positions (chair sitting, standing, floor sitting) used by cerebral palsied children with spastic diplegia. The results, analysed statistically, could be useful in suggesting treatment strategy for the improvement of hand function in such patients. For this study, 27 children with mild or moderate spastic diplegia were chosen. They were patients of the Rehabilitation Hospital, Yonsei University Medical Center. Both dominant and nondominant hands were tested by the Box and Block Test. Bilateral hand function was tested by bead stringing and card sorting activities. Collected data was analysed using univariate, and MANOVA. Results were as follows: 1. The scores of children who walked showed no significant difference in any of the three postures. 2. The highest test scores in children who walked with assistance (aid /other person) were in the Box and Block Test for the nondominant hand, and in bead stringing for bilateral hand function. These scores occurred with the children in the chair sitting posture(p(0.05). The results showed that, in order to improve hand function in children with spastic diplegia, it is necessary to maintain a well supported upright trunk posture with varia- tions allowed for relevance to the chosen position of the hand activity being performed.