Objective To investigate the expression of Phosphorylated-signal transduction and activators of transcription 3 (P-STAT3) proteins in human prostate tissue from patients received re-peated biopsies. And consider the usefulness of detecting expression of P-STAT3 in early diagnosis of prostate cancer (PCA). Methods Fifty-eight patients (29 cases of PCA, and 29 cases of benign prostatic hyperplasia (BPH)) who had received repeated biopsies were involved in this study. Immu-nolabelling has been carried out on PCa patients' samples of cores from initially negative biopsies, typ-ical cores from cancer field, and other cores of the same batch biopsies showing no sign of prostate cancer. BPH patients' samples of cores from initial biopsies were set as control. All specimens were done immunohistochemistry stain with anti-P-STAT3 monoclonai antibody. The association of P-STAT3 expression in prostate tissues with the pathology result was evaluated. Results Compared with 10.3% in specimens of patients free of prostate cancer, the positive rate of anti-P-STAT3 stained in typical cores from cancer field, other cores of the same batch biopsies showing no sign of prostate cancer, and cores from initially negative biopsies, was 93.1 % (27/29), 82.8 % (24/29) and 86.2 % (25/29), respectively. There were significant differences of these values between former and laters' (X2=60.123,P=0.000). If P-STAT3 positive in tissue of initially biopsies was considered as the di-agnostic standard of prostate cancer, then it would show a relatively high sensitivity (86.2%) and specificity (89.7%). Conclusion IHC stain for P-STAT3 in prostate biopsy samples could be served as an adjunct to the current diagnostic approach to prostate biopsy for early diagnosis of pros-tate cancer.