The kidneys play important roles in organismal homeostasis by regulating osmolality and blood pressure, aiding in the reabsorption of water and nutrients, excreting wastes, and secreting hormones. Renal function is also important in the metabolism and excretion of drugs. Therefore, analyzing nephrotoxicity using renal markers is an important experimental step during drug development. Historically, renal function has been evaluated by measuring serum creatinine and blood urea nitrogen levels. Recently, more sensitive kidney biomarkers have been idenitified and renal function can be assessed by analyzing proteins such as FABP1/L-FABP and Osteopontin. In addition, renal markers can be used to assess kidney development during embryogenesis as well as pathological conditions such as renal failure and renal cell carcinoma.