Objective：To investigate the promoter region CpG island methylation status of glutathione S-transferase p1(GSTP1) gene in prostate carcinoma (PCa) tissues and to search for new molecular markers for the early diagnosis of PCa.Methods: The promoter region CpG island methylation status of 31 PCa,18 benign prostatic hyperplasia tissues (BPH) and 3 normal prostate tissues (NP) were examined by nest methylation-specific PCR (NMSP) technique,cloning and sequencing.Results: NMSP showed that the methylation rates of PCa,BPH and NP tissues were 83%,0% and 0%,respectively.The CG sites methylation rates of PCa,BPH and NP tissues were 96%,34% and 37%,respectively as determined by cloning and sequencing (P<0.01),with no significant difference found between those of BPH and NP tissues(P>0.05).A combination of NMSP and prostate-specific antigen(PSA)was better than PSA alone in screen of PCa.Conclusion: CpG islands of promoter region of GSTP1 gene is hypermethylated in PCa tissues.NMSP is sensitive and specific in detection of GSTP1 methylation,which may serve as a new method for early screen of prostate carcinoma.