Background/aim: The GSTP1 and RASSF1A methylations that were considered as prostate cancer-specific molecular biomarkers have been extensively reported in Western/American patients with prostate cancer but are rarely reported in Southeast Asian patients. In the present study, the methylation status of the GSTP1 and RASSF1A promoters was evaluated in prostate cancer (PCa) and benign prostate hyperplasia (BPH) tissues from Vietnamese men. Materials and methods: The accuracy of methylation-specific polymerase chain reaction (MSP) was validated to analyze the methylation pattern of GSTP1 and RASSF1A in 59 PCa and 37 BPH patients, respectively. The methylation status was confirmed by the sequencing of cloned MSP products. The association between methylation status and the clinical and pathological parameters of tumors was statistically analyzed. Results: The methylation of GSTP1 and RASSF1A was detected in 39/59 and 19/59 PCa patients and in 4/37 and 10/37 BPH patients, respectively. The methylation frequency of GSTP1 was significantly associated with PCa (P < 0.01). The RASSF1A methylation frequency (32.2%) observed in the study was lower relative to that detected in other populations. Conclusions: GSTP1 and RASSF1A methylation was accurately detected using the validated MSP method and can be used as a biomarker to diagnose prostate cancer.