Recently, adipose tissue has been reported as a source of adult stem cells (Hombach-Klonisch et al. 2008). A high yield of adipose-derived mesenchymal stem cells (ADSCs) can be obtained with minimal discomfort under local anesthesia (Casteilla & Dani 2006). Following reports by Zuk et al. (2001, 2002), many studies have examined the characteristics, plasticity, and inducibility of ADSCs. Embryonic mesoderm-derived adipose tissue comprises a heterogeneous population of smooth muscle cells, fibroblasts, adipocytes, mast cells, and endothelial cells (Hausman 1981; Hausman & Campion 1982; Pettersson et al. 1984). ADSCs are adherent in vitro, maintaining their mesenchymal phenotype and plasticity toward the mesenchymal lineage after many passages in culture. These cells have been molecularly characterized using a panel of multiple mesenchymal differentiation markers (Lee et al. 2004; Dicker et al. 2005;Wagner et al. 2005; Oedayrajsingh-Varma et al. 2006; Table 1). In addition, they have been found to differentiate into multiple cell types in vitro, including adipocytes, chondrocytes, osteoblasts, cardiomyocytes, and vascular endothelial cells (Majumdar et al. 2000; Zuk et al. 2001; Halvorsen et al. 2000, 2001; Rangappa et al. 2003; Planat-Benard et al. 2004b; ; Konno et al. 2010). Moreover, ADSCs reportedly exert positive effects on patients with graft-versus-host disease occurring after bone marrow transplantation, suggesting an immunomodulatory function (Lombardo et al. 2009). In this review, we describe the methods and mechanisms underlying ADSC differentiation into multilineage cells.