Diabetes mellitus is a well-known risk factor for coronary artery disease (CAD), which can lead to acute myocardial infarction, chronic myocardial ischaemia and heart failure. Despite the advantages in medical treatment, percutaneous coronary intervention (PCI) and coronary artery bypass grafting (CABG), morbidity and mortality is still high in patients with CAD. Along with PCI and CABG or in patients without options for revascularization, stem cell regenerative therapy in controlled trials is a possibility. Stem cells are believed to exert their actions by angiogenesis and regeneration of cardiomyocytes. Recently published clinical trials and meta-analysis of stem cell studies have shown encouraging results with increased left ventricle ejection fraction and reduced symptoms in patients with CAD and heart failure. There is some evidence of mesenchymal stem cell being more effective compared to other cell types and cell therapy may be more effective in patients with known diabetes mellitus. However, further investigations are warranted.