Blood glucose levels of rats with alloxan-induced diabetes dropped from hyperglycemic levels to hypoglycemic ones after treatment with bis-salicylidine ethylenediiminato oxovanadium (IV) complex for a period of 30 days. However, the diabetic condition reappeared after withdrawal of the vanadyl complex. Assay of carbohydrate-metabolizing enzymes clearly indicated that the vanadyl complex activates the glycolysis, glycogenesis and depresses the glycogenolysis and gluconeogenesis in diabetic rats, suggesting its insulin-like nature. The optimum dose of bissalicylidine ethylenediiminato oxovanadium (IV) complex to produce the normoglycemic level in the diabetic rats was 7.5mg of vanadium/kg body wt/day.