Primary CNS vasculitis is an uncommon disorder of unknown cause that is restricted to brain and spinal cord. The median age of onset is 50 years. The neurological manifestations are diverse, but generally consist of headache, altered cognition, focal weakness, or stroke. Serological markers of inflammation are usually normal. Cerebrospinal fluid is abnormal in about 80–90% of patients. Diagnosis is unlikely in the presence of a normal MRI of the brain. Biopsy of CNS tissue showing vasculitis is the only definitive test; however, angiography has often been used for diagnosis even though it has only moderate sensitivity and specificity. Granulomatous vasculitis is the most common pattern of vasculitis (around 60% of cases), and β-amyloid deposition is present in almost 50% of these patients. Several subsets of PCNSV have been identified, which differ in terms of outcomes and optimal management. The size of the affected vessels varies and determines outcome and response to treatment. Early recognition is important because treatment with corticosteroi15ds with or without cytotoxic drugs can often prevent serious outcomes. Cyclophosphamide (CYC) and mycophenolate mofetil appear to be effective for the induction of remission. Rituximab may be helpful in patients who are intolerant or respond poorly to CYC. The differential diagnosis includes reversible cerebral vasoconstriction syndromes and secondary cerebral vasculitis.