Objective To study the expression and localization of TGFβ1 and its signal transducer Smad2 and Smad4 which play important roles during testicular development and spermatogenesis in alpaca testis. Methods The whole testes were obtained from alpacas aged 24 months(n=3) at the Scientific Research Base of Shanxi Agriculture University. The protein expressions of TGFβ1、smad2、smad4 in alpaca testes were examined by Western blotting and SABC. Results The distributions of TGFβ1、Smad2 and Smad4 in the testes of alpacas aged 24 months w