Background Recent studies have suggested that estrogens are involved in normal and abnormal prostate growth,though their exact role is still controversial. Oestrogens exert inhibitory and stimulatory effects on prostate gland, but the expression of oestrogen receptor-α (ERα) and oestrogen receptor-β (ERβ) in malignant prostate tissue remains unresolved. We determined ERα and ERβ in prostate cancer and investigated the relationship between expression of ER and pathological features of prostate carcinoma.Methods Thirty-two cases of prostate cancer, 12 cases of normal prostate tissue and 32 cases of benign prostate hyperplasia were analyzed for the expression of ERα and ERβ using semiquantitative, reverse transcription polymerase chain reaction (RT-PCR) and the products sequenced.Results Comparisons of the normal, hyperplastic and tumour prostate tissues indicated an overexpression of ERα in tumour specimens (P＜0.01). However, the expression of ERβ significantly reduced in tumour tissues compared with normal and hyperplastic specimens (P＜0.01), suggesting that severe pathological features of prostate cancer were associated with lower ERβ expression. Spearman analysis showed negative correlation between ERβ expression and tumour stage, grade (-0.67, -0.43, respectively, both P＜0.05), and a positive correlation between ERα expression and tumour stage, grade (0.51, 0.57, respectively, both P＜0.01). Our analysis also showed that hormone refractory, prostate cancer, compared with hormone dependent, prostate cancer, displayed a decreased expression of ERβ (P＜0.01) and an increased expression of ERα.Conclusions ERa and ERβ may play important roles in the development of prostate cancer. The decrease in ERβ expression is associated with higher Gleason grade tumours and prostate cancer with higher metastatic potential. The loss of ERβ could be one of the key processes leading to uncontrolled growth of prostate epithelial cells.