Transplantation of human endothelial progenitor cells (hEPCs) may improve vascularization and left ventricular function after myocardial infarction. The scope of this study was to explore, whether cross-linking of EPCs may enhance the deposition of cells in the rat heart after clinical-like, intracoronary transplantation. To this end, 111 In-oxinate-labeled hEPCs were infused by a minimally invasive technique into the coronary arteries of immunosuppressed Wistar rats under control conditions and after ischemia/reperfusion. In a second set of experiments hEPCs were treated with phytohemagglutinin to create small cell clusters prior to transplantation. Continous three-dimensional HiSPECT images for 1 h and after 48 h revealed that cell deposition was significantly higher when hEPCs were cross-linked. Therefore, cross-linking of hEPCs may provide a promising approach to enhance the number of trapped cells also in a clinical setting.