Objective: Sorafenib has been recommended as first-or second-line treatment for metastatic renal cell carcinoma(mRCC)by several guidelines.The objective of this study is to evaluate the efficacy of Sorafenib treatments on Chinese patients with mRCC.Methods: The characteristics and outcomes of 140 mRCC patients treated with sorafenib monotherapy from two large-volume Chinese centers were retrospectively reviewed to evaluate the long-term efficacy and safety of sorafenib in Chinese patients and identify the prognostic factors associated with response to sorafenib.The primary endpoint was overall survival(OS),and the secondary endpoints included progression-free survival(PFS),objective response rate(ORR),disease control rate(DCR),and safety.Results: The median follow-up time was 32 months.The median OS and PFS were 24 months(range,3-88 months)and 16 months(range,0-88 months),respectively.KaplanMeier and Log rank analyses revealed that patients with clear cell carcinoma had a greater OS(P=0.001)while sarcomatoid differentiation(P=0.045)and disease progression(P=0.010)negatively impacted OS.Furthermore,efficacy analysis revealed that 3(2.1%)patients achieved complete responses,28(20.0%)patients experienced partial responses,88(62.9%)patients had stable disease,and 21(15.0%)patients developed progressive disease.Moreover,the ORR was 22.1%,and the DCR was 85.0%.Most adverse events were classified as grades 1 or 2 with only 14(10.0%)patients experiencing severe adverse effects(grade 3).Conclusions: Sorafenib monotherapy can achieve promising OS and PFS for Chinese patients with mRCC,especially in those with clear cell carcinoma,with manageable adverse effect events.