Adult stem cells (ASC) have becoming a great domain of research by their promising interest for the regenerative medicine. For some years, the number of publications has been increasing, displaying the potential of ASC to differentiate in all tissue-lineages, challenging the previous dogma that ASC were restricted to give rise only to specific cells from their tissue of origin. Among the diversity of ASC, hematopoietic stem cells (HSC) have been the most studied and their use in the clinical setting is largely documented. Commonly, HSC have been harvested from the bone marrow, but for some years, two others sources, the peripheral blood and the umbilical cord blood have been introduced. All these HSC posses their own molecular characteristics and degree of maturity and represent a more or less good candidate to participate in the cellular-based tissue regeneration. We have reviewed the different parameters allowing to define which subset could be the more favorable such as the accessibility to the pool of HSC; the quantity of available cells; the tolerability of host-engraftment and the capacity of the cells to home correctly to the required site of damaged. Besides, recently, the molecular profiling of HSC has allowed identifying which subset posses the more promising characteristics.