OBJECTIVE: To analyze neurological manifestations in hypereosinophilic syndrome. Background. According to Chusid et al (1975), the neurologic manifestations in hypereosinophilic syndrome were paralysis, seizure, abnon-nal EEG finding, and neuropathy. According to Weaver(1988), eosinophil-induced neurotoxicities were characterized by axonal neuropathy, cerebral infarction, and dementia. METHOD: We analyzed 29 patients with neurologic manifestations and hypereosinophilia who visited Kyung-hee medical center during Aug. 1991-Jul. 1994. White blood cells were differentiated by the Coulter STKS S-plus machine and confirmed manually, if hypereosinophilia had been detected, by two clinical pathologists. Symptoms, signs, imaging studies, latoratory studies and biopsies were analyzed. RESULT: The mean age was 47.2 years and the mean eosinophil count was 2700/cu mm. Main symptoms were hemiparesis(31.0%), dysesthesia(20.7%), headache(20.7%), dysarthria(13.8%), paraparesis(10.3%), seizure(6.9%), myalgia(6.9%), confusion(6.9%), vertijo(6.9%), diplopia(6.9%), 14patientswereshowntohavecerebrovasculardisease, 5patientsmeningoencephalitis, 4patientsperipheralneuropathy, 3 patients myelopathy. CONCLUSION: Cerebrovascular diseases (48.3%) were most common neurologic disease in hypereosmopluc syndrome. Others were meningoencephalitis(17.2%), polyneuropathy(13.8%), myelopathy(IO.3%), eosinophilia-myalgia syndrome(6.9Yo), temporal arteritis(3.4%).