As part of the "Connecting Mathematics Learning through Spatial Reasoning" project, a Spatial Reasoning Mathematics Program (SRMP) intervention was implemented with one cohort of 30 students in grades 3 through 4. The SRMP embedded transformation skills in learning sequences comprising repeating and growing patterns, 2D and 3D relationships, structuring area and perimeter, directionality and perspective-taking. Analysis indicated a significantly better gain by the experimental group on the PASA-2 measure of awareness of pattern and structure and on the PASA-Sp assessment of spatial ability at the post-SRMP period. However, there were no significant differences found between groups on the PATMaths4 test of mathematics achievement. Qualitative analyses indicated that students demonstrated the development of complex spatial concepts well beyond curriculum expectations. The SRMP highlighted the important role of patterning and spatial structuring in the formation and representation of spatial concepts.