PURPOSE: Hemophagocytic lymphohistiocytosis (HLH) presenting with neurologic manifestationhas a poor prognosis due to delayed diagnosis and treatment. We investigated the time between onset of symptoms and diagnosis of HLH and clinical findings and outcome in patients with HLH presenting with neurologic manifestation. METHODS: We retrospectively assessed 24 patients with HLH in Seoul National University Children's Hospital from January 2002 to December 2010. Sex, age on diagnosis, symptoms, laboratory findings, time between onset of symptoms and diagnosis of HLH, cerebral spinal fluid (CSF) findings and brain magnetic resonance imaging (MRI) findings were reviewed. RESULTS: At diagnosis, 7 children (29.2%) had neurologic symptoms, including seizure (n=6) and right side weakness (n=1). Time to diagnosis from onset of symptoms ranged between 7 and 385 days in patients with neurologic symptoms and between 2 and 87 days in patients without neurologic symptoms. Five patients had brain MRI abnormalities; radiologic findings were multiple high signal intensity lesions on T2-weighted image (n=3), focal high signal intensity lesion followed by severe cerebral edema (n=1), and diffuse cerebral atrophy (n=1).Of these 7 patients, 4 died, 1 underwent stem cell transplantation and was followed, 1 was followed after completion of therapy without neurologic sequelae, and 1 is still under treatment and has mild neurologic sequelae. CONCLUSION: HLH presenting with neurologic manifestation is difficult to distinguish from other diseases because of nonspecific symptoms and imaging findings. However, HLH is treatable with chemotherapy and stem cell transplantation, so it is important to consider HLH in a patient with neurologic disease that is unresponsive to treatment and accompanies systemic symptoms.