Purpose <p>Body composition varies by race and ethnicity and influences cancer prognosis, but the associations of body composition with pathological characteristics in renal cell carcinoma (RCC) remain unclear. This study investigated body composition variation and its association with RCC histology, tumor grade, and stage.</p> Methods <p>Using preoperative imaging scans, we measured area (cm²) and radiodensity of adipose tissue sub-compartments and skeletal muscle. Area measurements were normalized for height squared (cm²/m²) to calculate intermuscular, visceral, and subcutaneous adipose tissue and skeletal muscle indices (e.g., IMATI, VATI, and SATI). Logistic regression analyses were used to estimate odds ratios (ORs) and 95% confidence intervals (CIs).</p> Results <p>A total of 268 patients were included. Compared to non-Hispanic White patients, SATI was higher in Hispanic (<i>p</i> &lt; 0.01) and American Indian (<i>p</i> &lt; 0.05), and VATI was higher in Hispanic patients (<i>p</i> &lt; 0.05). High IMATI (Quartile 4 vs 2) was associated with increased odds of clear cell subtype (OR 6.93, 95% CI:1.74–27.58), while low IMATI (Quartile 1 vs 2) was associated with reduced odds of advanced-stage (OR 0.27, 95% CI:0.10–0.72). Increase in each SATI quartile was associated with higher odds of high grade (OR 1.52, 95% CI:1.02–2.28). High visceral adipose tissue radiodensity (Quartile 4 vs 1) was associated with increased odds of advanced stage (OR 4.72, 95% CI:1.25–19.41). For all adiposity measurements, the low adiposity/low SMI phenotype was associated with high grade with about three-fold increased odds compared to the low adiposity/high SMI phenotype.</p> Conclusions <p>These findings suggest body composition varies across racial and ethnic groups and is associated with RCC pathological characteristics.</p>