The beta-type transforming growth factors (TGF beta s) are secreted proteins, which play an important role in regulation of cell proliferation and differentiation in the embryonic inner ear. In order to probe into the effect of TGF beta s on the hair cell regeneration, expression of TGF beta 1, TGF beta 2 and TGF beta 3 proteins were examined by using immunohistochemistry in the chicken basilar papilla during hair cell regeneration following gentamicin ototoxicity. Ten-day-old chickens received daily subcutaneous injection of gentamicin sulfate 50 mg/kg of ten consecutive days. The animals were allowed to survive 1,3,7,14,21 and 28 days before sacrifice and preparation for examination of the expression of TGF beta 1, TGF beta 2 and TGF beta 3 proteins. Immunostaining results demonstrated that TGF beta 2 and TGF beta 3 proteins were observed in the damaged region of basilar papilla. TGF beta 2 and TGF beta 3 proteins positive cells were limited to the lumenal nuclear layer within the damaged region. TGF beta 1 protein positive cell was not found in our study. These results indicated that TGF beta 2 and TGF beta 3 proteins might play a role in regulating proliferation of the supporting cells immigrated into the lumenal nuclear layer during hair cell regeneration.