The modified pullulan derivatives having N-phenylurethane and N-hexylurethane groups in the side-chain (PI-PL and HI-FL) have been synthesized by the reactions of pullulan with phenyl isocyanate (PIC) and hexyl isocyanate (HIC), respectively. The structure of the derivatives was characterized by gel permeation chromatography, IR and H-1 NMR spectroscopy. From the measurement of differential scanning calorimetry of PI-FL and HI-FL with various degrees of addition (DA) in the range of 0-3, it was revealed that both the derivatives showed a clear glass transition temperature (T-g), which decreased with the increasing DA of PIC and HIC. The pullulan derivatives were water-resistant and had good solubility in general organic solvents.