The primary use of vascular corrosion casting has been and likely will continue to be for describing the 3-dimensional anatomy of the microvasculature of organs and tissues. In these studies the assumption is made that the corrosion cast faithfully replicates the anatomy, dimensions, and distribution of the vasculature of these tissues and organs. If this assumption is accurate, and it appears to be nearly so in tissues where measurements have been made, it follows that the casts should lend themselves to quantitative measurements. I summarize here some simple quantitative measurements we have made from corrosion casts. For these studies, cannulas were inserted into arteries leading to the organ of interest in anesthetized animals, and the blood was removed by flushing with Ringer solution or buffered saline, at physiological temperatures and pressures. Resin consisting of Mercox (or Mercox diluted with methyl methacrylate monomer) and catalyst was infused via the same cannula until the onset of polymerization.