alpha-Galactosidase and beta-galactosidase activities have been determined in leukocyte preparations from 100 randomly selected Chinese adults. For alpha-galactosidase, two groups with low activities were identified: group I consisted of 3 females having activities below 40% of normal, and group II consisted of 5 males and 1 female with activities about 60% of normal. Family studies suggested that these low alpha-galactosidase activities are genetically determined. Only 1 individual was found to have about 50% of normal beta-galactosidase activity; presumably he is a carrier for beta-galactosidase deficiency (GM1 gangliosidosis).