The present study was concerned with the effects of pre-play experience on problem-solving activities in preschool children. Fifty-six five year old and 56 six year old children were randomly assigned to one control and three experimental groups. Manipulation being play group was allowed to play with a peer with the materials to be used in the task; manipulation on and non-play group was asked to imitate the E in manipulating materials to be used in the task; and play and non-manipulating group was given the opportunity to play with a peer with toys that were not related to the task. The extra experience lasted for 7 minutes. During task session, all Ss were individually pre sented with the problem task whose solution called for joining several materials together to obtain a goal-object (a toy puppy) so placed that it could not be reached without a medium. The main results suggested that experience of manipulating materials helped the construction of more complex tools for problem-solving and Ss consequently showed more rapid approach toward solution. While play-experience improved tool-construction during task process, Ss showed as a result a more gradual approach to the solution. Results also showedthat there were age differences in the effects of play-experience on problem-solving activities and in the types of play activities in the pre-task session. These results were interpreted as showing that during pre-play session, Ss were training their intentional plans of activities. The age-differences observed were due to the children's different level of development in such activities.