Objective: Behcet's disease is the association of recurrent aphthous stomatitis with genital ulceration and eye disease. Neurologic involvement patterns include meningomyelitis, a brain stem syndrome, pyramidal and extrapyramidal abnormality and stroke. In the present study, subclinical involvement was investigated by using P300 in Behcet's patients without neurological manifestation. Methods: Fifteen patients and 15 healthy volunteers were accepted for the study. P300 from vertex (Cz) electrode sites of the 10-20 system using electrodes and motor response time were recorded. Results: Patients had significantly prolonged latencies of P300 as compared to normal controls (p=0.013) but no significant differences in amplitude (p=1.000). Patients showed a significantly delayed motor response time than controls (p=0.006). Nine patients (60 %) had P300 latency and eight patients (53.3 %) had motor response time values exceeding the mean of controls by two standard deviations. Conclusion: The findings suggest that the P300 measures and motor response time may reflect subclinical neurologic involvement in Behcet's disease.