Abstract: Objective: To evaluate the effect of transforming growth factor-β1 (TGF-β1) in myogenic differentiation of human rhabdomyosarcoma (RMS). Methods: Myogenic differentiation was ana-lyed as the mRNA level of myosin heavy chain (MyHC) by reverse transcription-polymerase chain reaction (RT-PCR). Immunofluorescent staining was used to detect the expression of MyHC, Sarcomeric-Actin and MyoD1. Immunohistochemistry was used to detect the expression of TGF-β1 and MyHC in 49 cases of rhabdomyosarcoma. Results: Exogenous TGF-β1 downregulated expression of MyHC mRNA. Moreover, treatment with TGF-β1 significantly decreased the number of MyHC and Sarcomeric-Actin-expressing cells when compared with the control (P<0.05). However, TGF-β1 treatment didn't change the expression of MyoD1. There was a close negative correlation between the expression of TGF-β1 and MyHC in RMS tissues (r=-0.661, P<0.05). Conclusion: TGF-β1 may inhibit myogenic differentiation independent of its effects on MyoD1 in RD cells. TGF-β1 signal transduction may play an important role in myogenic differentiation of RMS cells.