Purpose: To evaluate the role of Prostate specific membrane antigen (PSMA) ligands PET/CT in detecting the primary prostatic tumor and metastatic disease in the initial staging of intermediate and high-risk prostate cancer patients. Materials and methods: This prospective study included 112 males with histologically proved prostatic adenocarcinoma in the initial staging phase. The patients' data and images were analyzed for the detection rate of primary and metastatic prostatic cancers based on PROMISE criteria, and for predicting the metastatic risk among different patients' groups according to their serum prostate specific antigen (PSA) level, International Society of Urological Pathology (ISUP) tumor grade and multi-parametric magnetic resonance imaging tumor stage (mpMRI-T-stage). The maximum standardized uptake value (SUVmax) of the primary prostatic tumor was evaluated in relation to the PSAlevel and Gleason-score. Results: The primary tumor was detected in 98.2% of patients, there was statistically significant agreement between the biopsy results and PSMA-PET/CT findings (P < 0.001), positive correlation between the prostate cancer SUVmax and the PSA-level as well as the Gleason-score. Metastatic disease was detected in 55.4% of the patients. Serum PSA-level, biopsy ISUP and mpMRI-T-stage were important predictors of metastases. Moreover, regression analysis revealed that the high-risk group was eight times more likely to have metastatic disease than the intermediate-risk group. Conclusion: The results validate the role of PSMA-ligands PET/CT in the initial staging of intermediate and high-risk prostate cancer patients as it could predict disease metastases. It also emphasizes that risk-stratification is a statistically significant prognostic factor for metastatic disease.  Kulcsszavak: PSMA-PET/CT, prostate cancer, initial staging, metastatic prostate cancer