Central nervous system involvement in Behçet disease (BD) has been well documented, but studies evaluating peripheral nervous system involvement are relatively uncommon.The aim of this study is to evaluate the frequency and characteristics of peripheral nervous system involvement in BD.Sixty-nine BD patients (36 women, 33 men) followed by neurology and dermatology outpatient clinics between October 1999 and October 2004 were enrolled into study. A careful history was taken and physical and neurologic examinations were done. All other medical causes that may be related to peripheral nervous system involvement were studied. All patients underwent nerve conduction studies using standard electrophysiologic procedures.Peripheral nervous system involvement was detected in 13 patients. There was no sign and symptom related to peripheral nervous system involvement in these patients. Causes other than BD were found in 5 patients with polyneuropathy. Asymptomatic delay in conduction velocities of the median nerves was detected in 3 patients. In 5 patients with clinically evident peripheral nerve involvement due to BD, 3 had sensorimotor and 2 had sensory axonal neuropathies.Axonal type polyneuropathy may be seen in BD patients. Peripheral involvement may be detected by electrophysiological examinations in asymptomatic BD patients.