Objective To investigate the expression of T-cadherin in prostate cancer as well as its effect on proliferation of prostate cancer DU 145 cells. Methods The expressions of T-cadherin mKNA in 40 prostate cancer and adjacent noncancerous tissue samples were determined by KT-PCH. DU 145 cells were infected with Ad-GFP-T-cadherin and Ad-GFP, each at a titer of 1. 6 × 10 12 pdf/ml, then determined for proliferation level by MIT assay, and for expression levels of P21 and cyclin D1 by Western blot, using uninfected cells as blank control. Results The expressions of T-cadherin in 38 of 40 (95%) prostate cancer tissue samples were down-regulated (P < 0. 01), indicating that the expression was correlated with the stage, Gleason grade and differentiation of prostate cancer. The expression level of P21 in DU 145 cells in Ad-GFP-T-eadherin group was significantly higher, while that of cyclin D1 was significantly lower, than those in Ad-GFP and blank control groups (P < 0. 01). However, the proliferation activity as well as P21 and cyclin D1 expression levels of DU 145 cells in blank control group showed no significant difference with those in Ad-GFP group (P > 0. 05). Conclusion The expression of T-cadherin was closely correlated with the occurrence of prostate cancer, which inhibited the proliferation of DU 145 cells through up-regulating the expression of P21 and down-regulating the expression of cyclin D1.