We describe the neurological involvement in brucellosis and revisited diagnostic criteria for neurobrucellosis.Patients with laboratory-confirmed brucellosis who were consequently hospitalized were observed prospectively in a brucellosis-endemic region. The neurobrucellosis was diagnosed by any one of the following criteria: (1) symptoms and signs consistent with neurobrucellosis; (2) isolation of Brucella species from cerebrospinal fluid (CSF) and/or presence of anti-Brucella antibodies in CSF; (3) the presence of lymphocytosis, increased protein, and decreased glucose levels in CSF; or (4) diagnostic findings in cranial magnetic resonance imaging or CT.Lumbar puncture was performed in 128 laboratory-confirmed brucellosis cases who had neurological symptoms and signs, and 48 (37.5%) were diagnosed as neurobrucellosis. The sensitivity of tube agglutination (TA) in CSF was 0.94, specificity 0.96, positive predictive value 0.94, and negative predictive value 0.96. Brucella bacteria were isolated from CSF in 7 of 48 patients (15%). The mean age of 48 neurobrucellosis patients was 42 years (SD, 19 years), and 16 (33%) were female. The most common neurological findings were agitation (25%), behavioral disorders (25%), muscle weakness (23%), disorientation (21%), and neck rigidity (17%). Cranial nerves were involved in 9 of 48 patients (19%). One patient was left with a sequela of peripheral facial paralysis and 2 patients with sensorineural hearing loss.Patients with severe and persistent headache and other neurologic symptoms and signs should be considered for neurobrucellosis in endemic regions and to possibly receive longer therapy than 6 weeks. Brucella TA with Coombs test in CSF is sensitive and specific by using a cutoff of ≥1:8.