Abstract Aims. We evaluated the feasibility, safety and efficacy of intra-myocardial injection of autologous mesenchymal stromal cells derived endothelial progenitor cell (MSC) in patients with stable coronary artery disease (CAD) and refractory angina in this first in man trial. Methods and results. A total of 31 patients with stable CAD, moderate to severe angina and no further revascularization options, were included. Bone marrow MSC were isolated and culture expanded for 6-8 weeks. It was feasible and safe to establish in-hospital culture expansion of autologous MSC and perform intra-myocardial injection of MSC. After six months follow-up myocardial perfusion was unaltered, but the patients increased exercise capacity (p <0.001), reduction in CCS Class (p <0.001), angina attacks (p <0.001) and nitroglycerin consumption (p <0.001), and improved Seattle Angina Questionnaire (SAQ) evaluations (p <0.001). For all parameters there was a tendency towards improved outcome with increasing numbers of cells injected. In the MRI substudy: ejection fraction (p <0.001), systolic wall thickness (p = 0.03) and wall thickening (p = 0.03) all improved. Conclusions. The study demonstrated that it was safe to treat patients with stable CAD with autologous culture expanded MSC. Moreover, MSC treated patients had significant improvement in left ventricular function and exercise capacity, in addition to an improvement in clinical symptoms and SAQ evaluations.