Objective: To evaluate the efficiency of chondrogenesis of human adipose-derived stem cells (ADSCs) induced by auricular chondrocytes from microtia via subcutaneous co-transplantation in nude mice.Methods: Human ADSCs and auricular chondrocytes were mixed at the ratio of 7∶3 and suspended in 0.2 ml of Pluronic F-127.The final concentration was 5.0×107 cells/ml and the mixture was subcutaneously injected into Balb/c nude mice as the experimental group (Exp group).The same quantity of auricular chondrocytes (Ctr.1 group) or ADSCs (Ctr.2 group) in 0.2 mi of Pluronic F-127 were set as positive and negative control groups respectively.The mixture of auricular chondrocytes (1.5×107 cells/ml) in 0.2 ml of Pluronic F-127 was set as the low concentration of chondrocyte control group (Ctr.3).8 weeks after transplantation,the newly generated tissue pellets were isolated for morphological examination, Haematoxylin and Eosin (HE) staining, Toluidine Blue staining and Safranin-O staining of glycosaminoglycan (GAG), Masson's Trichrome staining and immunohistochemical staining of type Ⅱ collagen, Verhoeff-iron-hematoxylin staining of elastic fibers.GAG content was determined by the Alcian Blue colorimetric method, and the mRNA expression of type Ⅱ collagen and aggrecan were examined by real time PCR.Results: The cartilage-like tissue with white translucent appearance and good elasticity were generated in Exp and Ctr.1 groups and.The tissue pellets in Ctr.2 and Ctr.3 groups were much smaller and the tissue in Ctr.2 was fiber-like.The mature cartilage lacunas could be observed in Exp and Ctr.1 groups, while rarely in Ctr.3 group and not in Ctr.2 group.The expression of cartilage-specific extracellular matrix such as type Ⅱ collagen, GAG content, aggrecan and elastic fibers in Exp group was similar to those of Ctr.1 group,whereas the expression of these extracellular matrix was obviously lower in Ctr.2 and Ctr.3 groups (P <0.01).Conclusion: Auricular chondrocytes from microtia can efficiently promote the chondrogenic differentiation and chondrogenesis of ADSCs by co-transplantation in vivo.