SummaryA case of Neuro‐Behcet's syndrome was reported clinicopathologically.A man of 37 years old at the time of death, which occurred seven and one‐half years after the first appearance of stomatitis and six and one‐half years after the first neurological manifestations. The illness began with buccal aphthae, erythema of the lower limbs and arthralgia. Thereafter neurological symptoms such as gait disturbance, numbness of the limbs and urinary disorder recurred. Soon afterwards genital ulcers, diplopia, forced crying and laughing succeeded. Neurologically paresis of oculomotor nerve, bulbar palsy, cerebellar signs, pathologic reflex and superficial and deep sensory disturbance below the level of Th4were noted. Ocular signs were not observed.Pathologically 1) Gliosed foci of softening with centrally situated cavities 2) Unsharply defined foci of demyelination 3) Perivascular accumulation of fat granule cells. The above mentioned changes were observed in the subcortical white matter, internal capsule, puta‐men, midbrain, pontine basis, medulla oblongata and spinal cord. In the cerebral cortex foci of spongio‐necrosis were noted rarely. Demyelination was noted in the optic nerve. In general inflammatory perivascular lymphocytic infiltrations remained mild. There was also cerebellar cortical degeneration.The clinical and the anatomical findings were discussed. Comparison with previously reported chronic cases suggests that this combination of a lowd‐grade diffuse encephalitis with severe necrotic focal lesion forms the characteristic pathological pattern in the p