Purpose:To further assess the role of androgen receptor gene CAG polymorphism in prostate cancer. Methods:DNA from 358 patients with prostate cancer were assayed for the number of CAG repeats. The length of CAG triplets and different clinical parameters were evaluated including age, PSA, stage, grade. Results:Only significant association between age at diagnosis and the length of CAG repeats was observed(P=0.007,γ=0.114).Conclusions:It was revealed from this study that the decreased number of AR gene CAG triplets was associated with the younger patient with prostate cancer at diagnosis.