This chapter are dedicated to theory of histopathology of central nervous system. Coloured diagrams and pictures of histopathology of central nervous system are given detail. A brief write up about contents of chapter is given as introduction in the beginning of the chapter. Normal histology of central nervous system is described initially to provide the basis for better understanding of histopathology. Histopathology of central Nervous System, neuronal injury, cerebrovascular diseases, meningitis, encephalitis, AIDS encephalopathy, Alziemer disease, multiple sclerosis, Parkinson disease, astrocytic tumor, oligodentroglioma, medulloblastoma, hemangioblastoma is described in detail with the help of 26 well illustrated diagrams.