Ultrastructural changes of two different types of protein bodies Pb-I (spherical with concentric ring structure) and Pb-II (irregularly-shape without concentric ring structure), contained in rice endosperm during germination were studied with a transmission electron microscope and scanning electron microscope. Pb-I and Pb-II in rice seed endosperm began to decompose at the first day of germination. Protein bodies in the endosperm adjacent to the scutellum decomposed earlier than those at any other part of the endosperm. Rough and ditch-like holes were observed on the surface of the protein bodies at the second day of germination. According to transmission electron microscopic observation, Pb-I decomposed from the outside of each body, but Pb-II decomposed from the irregular parts of each body. Most of Pb-II had decomposed by the fourth day of germination, but the holes on the surface of protein bodies were not observed at this stage. After the fourth day, we observed few protein bodies remaining. According to transmission electron microscopic observation, vacuolated protein bodies were observed at the sixth day, and thereafter, each of the vacuolated protein bodies fused to develop large vacuoles.