Prostate-specific membrane antigen (PSMA) is overexpressed in prostate cancer and is a well-studied target for therapy of this pathology with PSMA-specific radioligands. The aim of this work was to study the biodistribution of the domestic radiopharmaceutical 177Lu-DOTA-PSMA in BALB/c nu/nu (nude) mice with subcutaneously transplanted human prostate carcinoma 22Rv1. 177Lu-DOTA-PSMA was administered intravenously (0.30 MBq/mouse). Uptake of 177Lu-DOTA-PSMA in organs and tissues was calculated in percent of the injected dose. It was shown that the tumor concentration of 177Lu-DOTA-PSMA decreased from 2.46 ± 0.15%/g to 0.020 ± 0.007%/g within 120 h. The highest concentration of 177Lu-DOTA-PSMA (up to 14.578 ± 1.151%/g) was registered in the kidneys. Rapid elimination of 177Lu-DOTA-PSMA from other organs was also observed.