This chapter investigates the multipotent adult progenitor cells (MAPCs), exploring their unique properties, potential applications, and significance in regenerative medicine and orthopedics. Initially described by Catherine Verfaillie’s team in 2002, MAPCs are notable for their extensive expansion capability and pluripotent-like differentiation potential, including mesodermal, ectodermal, and endodermal lineages. MAPCs share phenotypic and functional characteristics with embryonic stem cells, such as pluripotency marker expression and self-renewal capacity. This chapter compares MAPCs with both mesenchymal stem cells (MSCs) and embryonic stem cells (ESCs), emphasizing the broader plasticity and distinct gene expression profiles of MAPCs. Detailed characterization, including their morphology, surface markers, and transcriptomic features, highlights their immunomodulatory and pro-angiogenic properties, which are crucial for tissue repair and regeneration. MAPCs have practical applications in immunomodulation, angiogenesis, and extracellular matrix production, making them valuable for treating chronic wounds, myocardial infarction, traumatic brain injuries, and bone repair. Preclinical studies demonstrate their potential in enhancing tissue repair, reducing inflammation, and improving recovery in various injury models. Clinically, MAPCs, particularly the MultiStem product by Athersys, have been evaluated in trials for acute ischemic stroke, myocardial infarction, and graft-versus-host disease, showing promise in safety and efficacy. Despite early research controversies, MAPCs hold significant potential in advancing regenerative medicine, especially in orthopedics, by addressing limitations of other stem cell therapies.