Monoclonal light chain-related renal diseases represent a unique collection of renal disorders with monoclonal light chain deposition underlying the pathogenesis of these disorders. Yet, despite this common pathogenic mechanism, each renal lesion is unique. In addition, these syndromes are unusual in that, unlike many other renal disorders, they are potentially reversible causes of renal failure. This review focuses on the pathogenesis of three light chain-related renal diseases: AL amyloidosis, granular light chain deposition disease, and cast nephropathy ("myeloma kidney"). Management of these renal lesions in relation to the different pathophysiologic mechanisms is also discussed. Treatment should be designed to decrease production of nephrotoxic light chains and to prevent the binding interaction between these light chains and the various structures of the nephron.