The purpose of this study was to compare and evaluate various hand functions in the most common position (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 patient. For this study, 27 children 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 striding and card sorting activities. Collected data was analysed using univariate correlation analysis and MANOVA. Results were as follows: 1) In chair sitting there was a significant positive correlation between dominant hand scores in the Bloc and Box Test and chronological age, gestation period, and time of treatment initiation. In bilateral hand function, card sorting scores correlated positively with time of treatment initiation. 2) In standing, there was a significantly positive correlation between dominant hand scores in the Block and Box Test and time of treatment initiation. 3) In floor sitting, there was a significantly positive correlation between the dominance hand scores in the Block and Box Test and the tine of treatment initiation. Bead stringing, a bilateral hand activity, correlated positively with gestation period and birth weight but negatively with the postnatal incubation period. 4) That score of children who walked showed no significant difference in any of the three postures. 5) Highest test scores in children who could nat walk were in the Box and Block Test for nondominant hand in bead stringing for bilateral hand function. There scores occurred with the children in thee chair sitting posture. 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 variations allowed for relevance to the chosen position of thee improvements hand activity being performed.