The anti-diabetic activity of methanolic extract of seed of Diplocyclos palmatus Linn.(Shivlingi) was evaluated in streptozotocin-induced diabetic mice.The antidiabetic potential was assessed by determining oral glucose tolerance, fasting blood glucose, urine glucose, liver glycogen content, serum lipid profile, change in body weight and histopathology. Streptozotocin was used to induce diabetes mellitus.The extract (150mg/Kg)was administered orally to normal and experimental diabetic male mice. Significant reduction in fasting blood glucose levels was observed in the treated diabetic animals from day 7 onwards. In oral glucose tolerance test, reduction of fasting blood glucose levels was noted after 60 min of extract administration. After 15 days of treatment with extract, 53.87% reduction in fasting blood glucose was observed in diabetic mice. Serum lipid levels reversed towards near normal and the loss of body weight was controlled in treated mice as compared to diabetic control. The extract treatment also showed a significant increase in the liver glycogen content and gradual decrease in level of urine sugar level. Seed of Shivlingi possesses significant anti-diabetic activity.