A case of GM1-gangliosidosis with high activity of hepatic neutral beta-galactosidase is reported. GM1-beta-galactosidase was deficient. Ganglioside GM1 was accumulated in the liver of this patient. Clinically this Japanese girl started convulsive seizures at 5 months of age, had hepatomegaly, and macular cherry-red spots, but lacked gargoylelike clinical characteristics. Correlation of clinical and biochemical data is discussed.