Summary: This protocol describes the procedures for estimating glomerular filtration rate in conscious mice based on Fluorescein Isothiocyanate-inulin (FITC-inulin) clearance following a single bolus intravenous injection. Diabetic Complication:Reference:1. Hem, A., Smith, A.J., and Solberg, P. 1998. Saphenous vein puncture for blood sampling of the mouse, rat, hamster, gerbil, guinea pig, ferret and mink. Lab Anim 32:364-368. 2. Sturgeon, C., Sam, A.D., 2nd, and Law, W.R. 1998. Rapid determination of glomerular filtration rate by single-bolus inulin: a comparison of estimation analyses. J Appl Physiol 84:2154-2162. 3. Qi, Z., Whitt, I., Mehta, A., Jin, J., Zhao, M., Harris, R.C., Fogo, A.B., and Breyer, M.D. 2003. Serial Determination of Glomerular Filtration Rate in Conscious Mice Using FITC-Inulin Clearance. Am J Physiol Renal Physiol.