The purpose of this study was to evaluate the effects of a play program in the creative thinking of preschool children. The study used a repeated measures experimental pretest-posttest design with control groups. The sample included 86 participants aged 5 to 6 years (53 experimental and 33 control participants). Before and after administering the program, two evaluation instruments were applied: The Torrance Test of Creative Thinking (Torrance, 1990) and Behaviors and Traits of Creative Personality Scale (Garaigordobil & Berrueco, 2007). The program consisted of a weekly 75-minute play session throughout the school year. ANOVA results showed that the program significantly increased the verbal creativity (fluency, flexibility, originality), graphic creativity (elaboration, fluency, originality), and behaviors and traits of creative personality. In the pretest phase, there were no differences in the creativity of boys and girls, and the program stimulated a similar level of change in both sexes. The discussion focuses on the importance of implementing creative programs with preschool children. (author abstract)