To evaluate the hypoglycemic effect of nano powder propolis, streptozotocin (STZ) induced diabetic rats were divided into 2 groups : diabetic control group and nano powder propolis (0.9ml) group. Then the rats were fed with nano-powder-propolis for 4 weeks. After 4 weeks, oral glucose tolerance test (oral GTT) was performed and blood sugar levels after 16 hours fasting, body weights, and blood lipid levels were measured. Finally, pancreas were collected and examined by histopathology and immunohistochemistry. In conclusion, the nano-powder-propolis was effective in the treatment of diabetes due to the reduction of blood sugar level and the regeneration of damaged ${eta}$-cells observed in streptozotocin-induced diabetic rats.