In this study, the urease-dextran non-covalent complexes in various molar ratios were synthesized and compared to the free enzyme in terms of pH, temperature, thermal and storage stabilities. Especially, the complex with a molar ratio of n(U)/n(DA) = 40/1 showed highest thermal stability and had ca. 1.4-fold at 25 degrees C and 2.5-fold at 80 degrees C higher activity than the free enzyme. The complex showed a high catalytic activity in organic solvent. In addition, the thermal and storage stabilities of urease were improved greatly as dextran complex, which has advantages for usage in practice.