This study was conducted to describe clinical and prognostic aspects of neurological involvement in Behcet's disease (BD). Patients referred for neurological evaluation fulfilled the criteria of the International Study Group for Behcet's Disease. We analyzed disability and survival by the Kaplan-Meier method, using Kurtzke's Extended Disability Status Scale (modified for ED) and the prognostic effect of demographic and clinical factors by Cox regression analysis. We studied 164 patients; of the 107 diagnostic neuroimaging studies: 72.1% showed parenchymal involvement, 11.7% venous sinus thrombosis (VST) and the others were normal. CSF studies were performed in 47 patients; all with inflammatory CSF findings (n=18) had parenchymal involvement. An isolated increase in pressure was compatible with either VST or normal imaging. The final diagnoses were VST (12.2 %), neuro-Behcet syndrome (NBS) (75.6 %), isolated optic neuritis (0.6 %), psycho-Behcet syndrome (0.6 %), and indefinite (11 %). VST and NBS were never diagnosed together. Ten years from onset of ED 45.1 % (all NBS) reached a disability level of EDSS 6 or higher, and 95.7+/-2.1 % of the patients were still alive. Having accompanying cerebellar symptoms at onset or a progressive course is unfavorable. Onset with headache or a diagnosis of VST is favorable. Two major neurological diagnoses in ED are NBS and VST. These are distinct in clinical, radiological, and prognostic aspects, hence suggesting a difference in pathogenesis.