The specialist research meeting on radioactive waste management was held in the Research Reactor Institute, Kyoto University, on November 13 and 14, 1990. This meeting has been held annually in the last several years. The meeting has taken up the topics related to both high and low level waste. This year, it was decided to place emphasis on low level waste and decommissioning waste. This report contains the proceedings of the research meeting. More than 70 persons from universities, government laboratories and private industries participated in the meeting and discussion. The lectures were given on the international trend of the disposal of low level radioactive waste, the performance evaluation test on natural barriers against the movement of radioactive nuclides in shallow underground, the environment parameters used for the calculation of dose equivalent, the construction of the high performance treatment system for fuel reprocessing waste, the present state and the technical development of nuclear facility decommissioning, and the investigation and evaluation of groundwater flow. The preparation of this proceedings was made possible by the cooperation of the authors and the assistance of Radioactive Waste Management Division of Research Reactor Institute. (K.I.).