To assess the underlying mechanism of visuomotor learning in children and its relation to the cerebral lateralization, intermanual transfer of learning was examined on a button-press task. The main experiment examined transfer of learning from one hand to the other for 36 right-handed 4-yr.-olds, 19 5-yr.-olds, and 8 adults. The experiment consisted of three phases. In the first and second of three phases, the subject performed the task with the right [(or left) hand, then with the left (or right)]. All age groups exhibited transfer from the left to the right hands; however, the 4-yr.-olds showed no transfer from the right to the left, whereas the other age groups showed transfer from the right to the left as well as left to right. Results were discussed in relation to the underlying mechanism of learning and hemispheric organization, and a new interpretation was proposed.