This study examines a series of children's drawings ("Draw for Math" tasks) to determine the relationship of students' spatial understanding and mathematical problem solving. Level of spatial understanding was assessed by applying the framework of central conceptual structures suggested by Case (1996), a cognitive developmental researcher. Drawings students constructed for the "Draw for Math" tasks also were categorized as schematic (i.e., proportional details included) or non-schematic (i.e., no proportional details included). Findings indicate that level of spatial understanding and use of schematic drawings both were significantly correlated to problem solving performance. Findings from this research have implications for policy and practice. The art classroom is an important context for developing students' spatial understanding and proportional thinking abilities associated with artistic as well as mathematical ability. Specific strategies to strengthen collaborative efforts of art specialists and their colleagues to integrate meaningful mathematically-based drawing activities are also suggested. (Contains 2 figures and 4 tables.)