© 2014 by Taylor & Francis Group, LLC. Cell therapy is currently generating great interest as a potential means of treating different kinds of cardiac diseases, including acute myocardial infarction, refractory angina, and chronic heart failure. In patients with acute myocardial infarction, the most common approach has been to deliver bone marrow-derived mononuclear cells (MNC) into the coronary artery supplying the jeopardized area a few days after its successful revascularization, with the objective of preventing late remodelling, which is known to negatively impact the long-term clinical outcome. This treatment is thus handled by interventional cardiologists. An extensive review of the most recent clinical trials1 outlines the still marginal bene ts derived from carefully conducted randomized trials. A more limited number of studies have assessed the effects of cell delivery in patients with refractory angina who have undergone cell injections as a catheter-based stand-alone procedure2,3 or as an adjunct to coronary artery bypass grafting (CABG).4-6 In this setting, the objective is rather to take advantage of the multiple cytokines and growth factors released by several types of cells to induce local angiogenesis and contribute to relieve ischaemic symptoms.7,8 The third category of potential candidates for cell therapy encompasses patients with chronic heart failure in whom the ideal goal is to partially regenerate areas of scarred myocardium to make them functional again. This chapter concentrates on these two latter patient groups (refractory angina and heart failure) as they are the only ones in which cardiac surgeons may and should be involved. Rather than trying to duplicate excellent and numerous review articles, this chapter is an attempt to address some of the basic questions that can be raised in light of the basic and clinical experience with stem cells, which has accumulated over these past 15 years.