The availability of advanced imaging techniques, especially that of MRI, has truly revolutionized the field of clinical neuroimmunology. MRI is extensively used in the diagnosis, prognostication, and disease monitoring of neuroimmunologic conditions. MRI biomarkers are integral parts of the current diagnostic criteria for multiple sclerosis, acute disseminated encephalomyelitis, and neuromyelitis optica. Advanced MRI findings reveal the importance of pathology in normal-appearing brain tissue, the relevance of brain and spinal cord atrophy, and the presence of gray matter pathology. MRI allows for monitoring of complex processes such as remyelination or axonal damage. Despite all the advances, demyelinating diseases cannot be diagnosed based on MRI findings alone. Many of the classic MRI markers are very sensitive but have poor specificity for the disease process. They therefore represent an important extension in the diagnostic armamentarium of the practicing neurologist but are not a replacement for solid clinical judgment.