BackgroundMonoamine oxidase A (MAOA) is a mitochondrial enzyme that is involved in prostate tumorigenesis and cancer metastasis. The predictive power of the preoperative clinical and pathological indicators for prostate cancer(PC) remains to be improved. To enrich evidence regarding the value of MAOA as a prognostic biomarker in clinical practice, this study explored the significance of MAOA expression as a prognostic marker for patients with PC after radical prostatectomy-pelvic lymph node dissection (RP-PLND).MethodsMAOA expression was analyzed in 50 benign prostate tissues and 115 low-intermediate risk and 163 high-risk PC tissues using tissue immunohistochemistry (IHC). Propensity score matching, survival analysis and COX regression analysis were conducted to investigate the correlation between high MAOA expression and progression free survival (PFS) in PC patients.ResultsMAOA expression was increased in PC patients, especially in those with high risk PC and pathological lymph node (pLN) metastasis. High MAOA expression was significantly associated with PSA recurrence for both low-intermediate risk PC patients (log-rank test:P =0.02) and high risk PC patients (log-rank test:P =0.03). Cox regression analysis revealed that high MAOA expression was an adverse prognostic factor for both low-intermediate risk PC patients (hazard ratio [HR] 2.74, 95% confidence interval [CI] 1.26–5.92;P =0.011) and high risk PC patients (HR 1.73, 95% CI 1.11–2.71;P =0.016). High MAOA expression was also significantly associated with PSA recurrence in high risk PC patients developed into castration-resistant prostate cancer (CRPC) and were receiving abiraterone therapy (log-rank:P =0.01).ConclusionsMAOA expression correlates with the malignant progression of PC. High MAOA expression may be a poor prognostic marker for patients with PC after RP-PLND. More careful follow up or potential of adjuvant hormonal therapy may be addressed for patients with high MAOA expression.Supplementary InformationThe online version contains supplementary material available at 10.1186/s12894-023-01285-8.