Niemann-Pick type C disease is an autosomal-recessive, inherited neurovisceral lipid storage disorder. This disease results from either protein NPC1 or HE1 deficiency, which leads to cholesterol metabolism disturbance and is characterized by early hepatosplenomegaly and progressive ataxia, dystonia, cataplexy, dysarthria, and dementia. We describe a 3 1/2-year-old patient with Niemann-Pick type C disease, who presented with regression in both cognitive and motor domains. Almost 10 months before admission to the hospital, the child developed progressive speech and behavioral changes, as well as gait disturbances with frequent falls. The examination demonstrated hepatosplenomegaly, ataxia, and vertical gaze palsy. Nerve conduction velocities demonstrated mild demyelinating peripheral neuropathy. Bone marrow examination revealed foam cells, and cholesterol esterification studies found massive accumulation of unesterified cholesterol and very low intracellular esterification of exogenous lipoprotein-derived cholesterol. These results indicate Niemann-Pick type C disease. Peripheral neuropathy is a rare complication in patients with Niemann-Pick type C disease, which certainly contributes to their neurologic deterioration.