Endothelial progenitor cells (EPCs) are thought to participate in endothelial cell regeneration and neovascularization in either a direct or an indirect way. The number of circulating EPCs is influenced by many factors like disease status, medication, age, and fitness level and is an independent predictor of disease progression and cardiovascular events. Experimental as well as clinical studies during the last 10 years clearly demonstrated that physical exercise training has a beneficial effect on endothelial function, which is a clear predictive value for cardiovascular mortality. Over the last years mainly clinical studies provided solid evidence for an exercise training induced mobilization of EPCs from the bone marrow, thereby possibly influencing the regeneration of the endothelial cell layer. This review will discuss the mechanisms how exercise induces mobilization of EPCs from the bone marrow with a focus on the influence on the redox balance.