The great potential of MRI for the diagnosis of inflammatory processes in the brain and spinal cord is discussed in the paper. The technique can produce images in all planes, precisely locate pathological changes in relation to bones, meninges and the cerebrospinal fluid spaces. Besides, it can show deep subcortical structures. Examples are presented of multifocal bacterial encephalitis and of abscesses of the brain on MR images without and with enhancement by means of contrast media containing Gadolinium. MR images of viral encephalitis frequently manifest specific patterns due to different neurotropism of particular viruses.