Objective: To determine whether fatty kidney disease deserves be designated as a distinct clinical entity similar to fatty liver disease. Methods: Analysis and interpretation of the literature in a novel conceptual framework. Results: The kidney contributes to hyperglycemia, hypertension, inflammatory cytokines, and thus to diabetes and metabolic syndrome. Fat accumulation in and around the kidney drives this process and contributes to progression of chronic kidney disease itself. Weight loss improves these complications of fatty kidney. Diagnosis currently must be inferred from comorbidities but ultimately should be made by imaging once the importance of fatty kidney disease is established, much like fatty liver disease. Conclusion: Fatty kidney disease merits designation as a specific clinical entity similar to fatty liver disease. Greater attention to this may help encourage research into ameliorating the negative consequences of fatty kidney disease and developing new therapies. Abbreviations: BP = blood pressure; CKD = chronic kidney disease; CT = computed tomography; ESRD = end-stage renal disease; FFA = free fatty acid; FKD = fatty kidney disease; GFR = glomerular filtration rate; MetS = metabolic syndrome; MRI = magnetic resonance imaging; NAFLD = nonalcoholic fatty liver disease; RAAS = renin-angiotensin system; SGLT2 = sodium-glucose cotransporter 2; SNS = sympathetic nervous system; T2D = type 2 diabetes; TG = triglyceride.