The purpose of this study is to develop and implement an alternative elementary mathematics curriculum to enhance creative problem solving ability. The curriculum consisting of three main elements was developed. The three elements are content knowledge, process knowledge and creative thinking skills. The curriculum contents and the units were developed by mathematics educators, elementary educators, psychologists, elementary school teachers and curriculum specialists for 3 years. In order to test the effectiveness of the developed curriculum, the 5 units based on a problem-based-learning (PBL) method were implemented in a 5th grade class as an experimental group during the second semester. For the comparison group the ordinary lesson based on the 6th national mathematics curriculum was implemented during the same period. Performance assessment was developed and used for the pre and post test. T-est was use to testify that the effect of the curriculum is statistically signigicant. The results of the test showed that the experimental group progressed significantly in the creative problem solving ability, but the comparison group did not.