The invertase inhibitor was isolated, purified and characterized biochemically and electrophorectically from sugarbeet roots. Acid and alkaline invertase was found in roots of sugarbeet. The acid invertase activity decreased during development whereas the alkaline invertase persisted throughout the foot development. The decreased activity of the acid invertase can be attributed to the presence of high inhibitor concentration at the maturity level. To characterize, the invertase inhibitor was isolated from the roots of H1-0064 variety of sugarbeet and purified to 104.5 folds using Sephadex G-100 column chromatography. Non-denaturing polyacrylamide gel electrophoresis of the ammonium sulphate and acetone preparation of the inhibitor showed S and 3 bands respectively, whereas the purified invertase inhibitor revealed single protein band near the dye-front, confirming the homogeneity and low molecular weight of the sugarbeet inhibitor. The inhibitor tested against theCandida utilisinvertase expressed optimum activity at pH 4.0 and 40°C. The inhibitor binds the enzyme in a reversible manner and was found to exhibit non-competitive mode of action representing constant Km with gradual decrease in Vmax of the enzyme.