A new type of gelatin microspheres was manufactured with the crosslinking method by using gamma-ray irradiation. Microspheres thus obtained were characterized by microscopic observation and enzymatic degradability. The mean diameter of the microspheres was in the range from 2.4 to 3.6 mum and the size distribution was quite small. The size decreased with increasing the shear rate of the emulsifier used in the preparation and was not affected by the radiation dose. The enzymatic degradability decreased with increasing the radiation dose and decreasing the gelatin concentration of the microsphere. In other words, the rate of the enzymatic decomposition of microspheres can be controlled by these two parameters. These trends were consistent with our previous results for the gel sheet made of gelatin. Their sorption of proteins was also investigated with the use of three types of proteins labeled by fluorescent pigment. From the fluorescence micrographs, it was observed that the gelatin microspheres adsorbed only proteins having the opposite charge. (C) 2004 Wiley Periodicals, Inc.