The central nervous system (CNS) consists of brain and, spinal cord. Brain is within the cranial cavity in the bony, skull and spinal cord is within the vertebral cavity of the, bony vertebra. The brain consists of cerebrum, cerebellum, pons and medulla oblongata. Histologically, it consists, of neurons and neuroglia. The neurons are specialized, cells involved in conduction of impulses. The neuroglial, cells include—astrocytes, oligodendrocytes, and ependymal cells. These glial cells provide support and nutrition to the neurons. The brain covered by dura, pia and arachnoid mater. The CNS infections can be divided depending upon the location of the infection such as meningitis, encephalitis, meningoencephalitis, routes of infection, direct implantation, local extension, and transport along the peripheral nervous system. Gliomas, poorly differentiated neoplasms, tumors of meninges, and metastatic tumors are common CNS tumors. Cerebrovascular diseases, intracranial hemorrhage, paraplegia, hemiplegia, demyelinating diseases, neurodegenerative diseases are other important topic are also included in this chapter.