Limitations associated with cardiac progenitor cell (CPC) therapy of myocardial infarction (MI) including poor engraftment, cell death and incomplete cardiac differentiation have hindered the efficacy of treatment in pre-clinical trials. Given that the extracellular environment plays an important role in regulating cell function and that it is significantly remodeled following MI, it is critical to understand how these changes impact the therapeutic potential of CPCs. In this study, we investigated how the alterations to the extracellular matrix (ECM) following MI impacted the regenerative potential of CPCs in vitro. Hearts were decellularized with 1% SDS prior to MI and 1 and 4 weeks post-MI (Fig A) and the composition of the left ventricle or scar was characterized through LC-MS/MS. While Periostin and Collagen I increased post-MI, Laminin decreased (Fig B). c-kit+ CPCs isolated from rat hearts 1 week post-MI were cultured on tissue culture plastic (TCP) coated with pepsin-solubilized ECM. Our results demonstrated that the healthy matrix promoted the expression of pro-angiogenic growth factors, while maintaining the cells in an undifferentiated state (Fig D,E). Alternatively, 1 week ECM promoted cell adherence (Fig C) and the expression of pro-survival growth factors (Fig D) and GATA-4 (Fig E). Cells cultured on 4 week ECM demonstrated significant differentiation towards vascular lineages through their expression of smooth muscle (TAGLN) and endothelial (VWF) markers. By characterizing how the changing ECM composition following MI impacts CPC fate, we may be able to develop therapeutic strategies that modulate cell fate/ function in vivo following implantation.