177Lu-PSMA is a new, promising treatment option in patients with metastatic castration-resistent prostate carcinoma (mCRPC). The radioactive-labeled medication is given intravenously in 1–6 cycles, in which the β‑radiation causes damage to the cellular DNA and eventually cell death of prostate cancer cells that express PSMA. In mostly retrospective studies, a decrease is seen in the serum-PSA level of ≥ 50% in 40–60% of patients that have been previously extensively treated. A survival benefit is observed, but mostly within non-randomized studies. The toxicity of treatment is relatively mild with grade I–II CTCAE xerostomia in 30–50% of patients and a passing grade III–IV CTCAE hematologic toxicity (thrombocytopenia, leukopenia) in 0–15%. The medication is under study in multiple prospective studies in patients with mCRPC and in one randomized clinical trial. The use of 177Lu-PSMA in patients with earlier phases of disease is explored. Until proven of benefit in RCTs, 177Lu-PSMA therapy remains experimental.