Objective: To evaluate the impact of preoperative body composition in patients with renal cell carcinoma (RCC) undergoing surgical treatment. Materials and Methods: This was a retrospective study of 52 patients with RCC undergoing total or partial nephrectomy. Body composition assessment was performed using the body mass index, together with computed tomography analysis at the level of the third lumbar vertebra to measure the area of visceral adipose tissue, as well as the area and density of skeletal muscle mass. Results: Malnutrition, obesity and inadequate skeletal muscle gauge (SMG) were associated with higher hospital length of stay (p = 0.028, p = 0.02 and p = 0.012, respectively). Although the rates of postoperative symptoms and readmissions were low, survival was better among the patients with an adequate SMG than among those with an inadequate SMG (p = 0.003). Conclusion: Among patients with RCC undergoing surgical treatment, preoperative body composition does not seem to be associated with the rates of perioperative complications, although an inadequate SMG seems to be associated with worse overall survival.