In this research aimed to determine the effect of Inquiry Based Science Education Program on supporting science learning for 60-72 months old children in preschool education. The study group consists of a total of 46 children, 23 of which are in test group in randomly selected schools and 23 of which are in control group. In this study, pre-test and post-test, quasi-experimental design with control group were utilized, General Information Form was used to gather information about parents and children, and the Science Learning Assesment Test was used to determine that children learn science. Inquiry Based Science Education Program developed by the researcher was applied to the children in the experiment group for three days a week during a total of 12 weeks. In order to determine the permanency of the test, Science Learning Assesment Test was re-applied to the children in the experiment group 4 weeks after the completion of the education program. T test for independent samples and t test for related samples were utilized in order to present the effect of Inquiry Based Science Education Program. There was a significant difference in favour of the experiment group between the total and sub-scores of the children in experiment and control groups from the Science Learning Assesment Test and its subtest (p<0.01). As a result of the test on the permanency of the education program, it was concluded that the effect of the education program continued (p>.05). In view of these findings, suggestions were provided for researchers and educators so that they can enhance the science learning of the preschool children.