Niemann-Pick C disease (NP-C) is characterized by the accumulation of unesterified cholesterol and glycolipids in the lysosomes of cells in the nervous system and visceral organs. Miglustat, an iminosugar reversibly inhibits glucosylceramide synthase, has been approved for the treatment of Niemann-Pick C disease. We treated five children with NP-C disease. The median age for the first neurological symptom onset was 7.5 years (range 5-9 years). They were treated by miglustat since the median age of 12.3 years (range 9-14). Before treatment, all cases had mental impairment, 4 cases had motor impairment, and 4 cases had difficulties in swallowing. After treatment, improvement in swallowing was the most prominent and immediate finding. Although the condition of swallowing quality deteriorated in some patients after 1 year of treatment, probably due to drug interruption, both penetration-aspiration scales and dysphagia severity scores did remain stable in 3 of 5 patients after 3.7-5.7 years of therapy. Other domains which improvement has been found include motor function, cognitive function, and borderline horizontal eye pursuit movement. This study suggests that miglustat can provide therapeutic benefits in neurological symptoms and stabilize the disease in children affected by NP-C.