Obesity, defined as a body mass index (BMI) >30 Kg/m2 [1] has been reported as a causal agent in 40% of renal cell carcinoma (RCC) cases [2,3]. Epidemiological studies have explored the connection between obesity and mortality [4] with some studies showing, perplexingly, that elevated BMI may improve survival outcomes, a phenomenon known as the “obesity paradox” [5,6]. The preponderance of these data have come from cohorts exclusively or predominantly of clear cell (ccRCC) histology [7], [8], [9], [10]. Nevertheless, RCC contains a wide range of histological features with specific risk factors, oncological aggressiveness, and unique metastatic patterns associated with different histologies [11], [12], [13], [14], restricting the generalizability of findings regarding BMI and outcomes in non-ccRCC histologies [14]. Herein, we sought to compare and assess association of BMI with oncological outcomes in clear and nonclear cell RCC.