Background: Tumor lysis syndrome (TLS) is an oncologic emergency which has been extensively documented in patients with hematological malignancies, but rarely described in patients with renal cell carcinoma (RCC). The objective of this study was to investigate the clinical characteristics and outcomes of TLS, a rare but life-threatening complication in RCC. Methods: Retrospective literature review and pooled analysis. Results: Ten cases of TLS were identified in patients with metastatic RCC (eight cases in published literature and two cases from our tumor registry). The median age of patients was 60 years (45-88). Seven cases (70%) of TLS were associated with a variety of treatment regimens, include sunitinib (42%), pazopanib (14.2%), nivolumab (14.2%), nivolumab and Ipilimumab (14.2%), and temsirolimus (14.2%). The median time to TLS from treatment 16 days (14-28). Three (33%) patients had spontaneous TLS. All patients had extensive metastatic disease at the time of presentation, with visceral metastases documented in 100% of TLS cases. The majority of cases were clear renal carcinoma (one case of sarcomatoid, and another with extensive rhabdoid feature). All cases were treated with aggressive supportive measures, and four patients received rasburicase. The mortality rate was 57% among seven cases of treatment related TLS. The mortality rate was 100% in the three patients with spontaneous TLS. Conclusions: TLS in RCC can occur both after treatment and spontaneously, and is associated with very high mortality. Our findings underscore the importance of heightened awareness, risk assessment, and early prevention of this previously underdiagnosed oncologic emergency.