The purpose of this study was to assess the effects of structure in instructions and materials on preschoolers' creativity. Thirty-two children ranging in age from 41 to 59 months comprised four experimental conditions of Structured Instructions-Structured Materials, Structured Instructions-Unstructured Materials, Unstructured Instructions-Structured Materials, and Unstructured Instructions-Unstructured Materials. An effort was made to equalize the groups on intelligence and baseline creativity from scores obtained in Session 1 using the Information Task from the Wechsler Preschool and Primary Scale of Intelligence and a three-dimensional patterns task derived from Moran, Milgram, Sawyers, and Fu. In session two the children were administered the appropriate instructions and materials and two days later in session three given the same instructions with a reverse in materials. Session four was administered to determine any long term effects of session two and three and therefore consisted only of unstructured instructions and materials. Analyses which were used included a 2 (instructions) x 2 (materials) analysis of covariance performed separately for sessions two and three. All analyses were covaried on age, sex, intelligence and baseline creativity. The results did not reach statistical significance, although mean differences suggest that structure in instructions and materials limit ideational fluency.