The present study aimed to evaluate the efficacy of cabazitaxel in Japanese patients affected by metastatic castration‐resistant prostate cancer (mCRPC) previously treated with a docetaxel‐containing regimen. In this retrospective study, 41 patients with mCRPC treated with cabazitaxel at Keio University Hospital were retrospectively reviewed. Cabazitaxel at a dose of 20‐25 mg/m² was administered every 3 or 4 weeks. Clinicopathological factors and laboratory data were collected to assess the prognostic factors for overall survival (OS) and progression‐free survival (PFS). An upfront dose‐reduction was required in 52.5% of patients due to their reduced general condition or advanced age. Prophylactic G‐CSF was prescribed to all the patients. Grade ≥3 neutropenia and febrile neutropenia occurred in 21 patients (53.6%) and 3 patients (6.8%), respectively. Treatment was generally well tolerated, with a median of 5 cycles (range 1‐17). Median PFS and OS from the start of cabazitaxel treatment were 4.4 and 15.0 months (95% CI 8.9‐21.2), respectively. Waterfall plot analysis revealed that a prostate‐specific antigen (PSA) decline >50% was noticed in n = 11 patients receiving cabazitaxel (26.8%). Univariate analysis revealed that poor performance status, PSA ≥100 ng/mL prior to cabazitaxel treatment, visceral metastasis, absence of grade 3/4 neutropenia during cabazitaxel therapy and neutrophil‐lymphocyte ratio were significantly associated with shorter overall survival. Multivariate analysis revealed that poor performance status, visceral metastasis, and the absence of grade 3/4 neutropenia during cabazitaxel therapy were the independent prognostic indicators for OS. The practical implication of our results might be to tailor cabazitaxel dosing on the basis of its hematological effects.