1. Six weeks after the injection of streptozotocin at 125 mg/kg i.p. in the AV line nondiabetic Chinese hamsters, the animals showed hyperglycemia, increased kidney, pancreas and stomach weights and stomach glucagon contents and depletion of insulin and glucagon in the pancreas. 2. Plasma beta-D-galactosidase and N-acetyl-beta-D-glucosaminidase were elevated; whereas alpha-D-glucosidase was decreased and alpha-D-galactosidase remained unchanged in the plasma. 3. In the kidney, streptozotocin-diabetes led to depression of alpha-D-mannosidase, beta-D-fucosidase and N-acetyl-beta-D-glucosaminidase activities in both 12,000 g supernatant and precipitate fractions, decreases in alpha-D-glucosidase in the supernatant only and no change in alpha-L-fucosidase, alpha-D-galactosidase, beta-D-galactosidase and beta-D-glucuronidase. 4. In the liver, significant increases in N-acetyl-beta-D-glucosaminidase, alpha-D-galactosidase, beta-D-galactosidase, beta-D-fucosidase, beta-D-glucosidase and alpha-D-mannosidase were found in either the supernatant or the precipitate fraction of the diabetic animals. The data indicate diabetes-dependent tissue-specific changes in glycohydrolases in the Chinese hamster.