This study is aimed to investigate the prognostic significance of inflammation indices, including neutrophil-to-lymphocyte ratio (NLR), monocyte-to-lymphocyte ratio (MLR), platelet-to-lymphocyte ratio (PLR), systemic immune-inflammation index (SII), and pan-immune-inflammation value (PIV) in metastatic castration-resistant prostate cancer (mCRPC) patients who had received lutetium labeled prostate-specific membrane antigen (177Lu–PSMA-617) therapy. Sixty-one mCRPC patients who received 177Lu–PSMA-617 treatment and followed up in Kocaeli University were included. The relationship between overall survival (OS) and progression-free survival (PFS) and clinical and laboratory parameters was analyzed by multivariate analyses. The mean age was 69.8 ± 6.9 years. The mean follow-up time was 53.2 ± 24 months. The median OS was 14 (95% CI: 8.8–18.1) and the median PFS was 10.4 (95% CI: 4.7–17.2) months. NLR ≥ 2.7, PLR ≥ 134.27, SII ≥ 570.39, PIV ≥ 408.59 were considered as elevated levels. In the multivariate analysis for OS, baseline ECOG performance score (HR: 1.92, 95% CI: 1.01–3.65, P = .046), high albümin (HR: 0.36, 95% CI: 0.16–0.82, P = .015), primary resistant total prostate-specific-antigen (PSA) (HR: 4.37, 95% CI: 1.84–10.35, P = .001), high NLR (HR: 3.32, 95% CI: 1.66–6.65, P = .001), high MLR (HR: 2.53, 95% CI: 1.35–4.76, P = .004), high PLR (HR: 2.47, 95% CI: 1.23–4.96, P = .01), and high SII (HR: 2.17, 95% CI: 1.09–4.32, P = .027) were associated with shorter OS. However, PIV was not associated with survival (P = .69). No factor other than the primer-resistant PSA could be identified as having an impact on PFS (for the PSA, HR: 4.52, 95% CI: 1.89–10.76, P = .001). In this study, pretreatment NLR, MLR, PLR, and SII demonstrate as powerful independent prognostic indices predicting survival in patients with mCRPC receiving 177Lu–PSMA-617 therapy.