An important outcome measure of effects of treatment for experimental spinal cord injury is excellent histology. One way to achieve this is to prepare the tissue for electron microscopy, which ensures the best preservation and requires resin embedding. "Semi-thin" sections of resin-embedded tissue (0.6-1.5 μm in thickness) may be stained and viewed in the light microscope to detect morphological features of the lesion such as various cell types, myelin and blood vessels. Specific areas of interest then may be chosen for thin sectioning preparatory to examination in the electron microscope when better resolution is required, such as searching for non-myelinated nerve fibers. The steps required to prepare the tissue for both light and electron microscopy are detailed in this chapter. A method for assessing the total numbers of axons, myelinated and non-myelinated, is included. Immunostaining for both light and electron microscopy also is described.