BACKGROUND: Inducing factors are currently used as a main method for the differentiation of bone marrow mesenchymal stem cells (BMSCs) into chondrocytes. OBJECTIVE: To investigate the collaborative stimulation of transforming growth factor beta1 (TGF-β1) and insulin-like growth factor 1 (IGF-1) to induce the directed differentiation of BMSCs to chondrocytes, and to explore the best inductive effect. METHODS: Rat BMSCs were isolated, cultured and purified using adherent culture. Then, different inducing factors were added in the induction medium: TGF-β1+IGF-1 group, TGF-β1 group, IGF-1 group, and control group without growth factors. Immunofluorescence was carried out at 21 days of induction. The expression of collagen type Ⅱ was evaluated by immuncytochemical staining at 7, 14 and 21 days of induction. RESULTS AND CONCLUSION: (1) Immunofluorescence detection of the TGF-β1+IGF-1 and TGF-β1 groups showed highly expressed collagen type Ⅱ (brown red-stained cytoplasm), while negatively expressed collagen type Ⅱ in the other two groups. (2) Findings from the immuncytochemical staining showed that the expression of collagen type Ⅱ was stronger in the TGF-β1+IGF-1 group than the TGF-β1 group (P < 0.01), and the expression was gradually enhanced with time. Meanwhile, there was also no expression of collagen type Ⅱ in the IGF-1 and control groups. To conclude, the combination of TGF-β1 and IGF-1 can achieve the better inductive effect on the chondrogenic differentiation of BMSCs in vitro.