Generalized gangliosidosis is a newly described storage disease characterized by a clinical syndrome of severe cerebral degeneration leading to death by the age of two years, the storage of a ganglioside in brain and viscera and of a mucopolysaccharide in viscera, and severe bony abnormalities which resemble those seen in Hurler's syndrome. Genetic studies reveal the disorder to be pan-ethnic in distribution, probably transmitted as an autosomal recessive trait. The ganglioside is identical to ganglioside GM1; the mucopolysaccharide is structurally similar to keratan sulfate. A profound deficiency of β-galactosidase has been demonstrated using both the ganglioside and the mucopolysaccharide which accumulate as substrates. Enzyme assays of tissues and body fluids may be helpful in identifying the homozygote state. © 1969 The C. V. Mosby Company.