The wholesomeness studies on irradiated foods and the evaluation of the data obtained have been conducted at both national and international levels. The conclusion of the FAO/IAEA/WHO Expert Committee on Wholesomeness of Irradiated Food in 1980 that irradiated foods treated with doses up to 10 kGy are safe for human consumption are being significantly influencing on the regulatory circumstances, in individual countries as well as a regional economic community. Principles of the wholesomeness evaluation, importance of radiation chemical considerations, methodology of toxicological testing and the interpretation of in vitro and in vivo toxicity studies are discussed. Emphasis is placed on the progress of methods for wholesomeness studies and data evaluations and also on the importance e of comparative assessments together with safety problems concerning other food treatments and environmental factors.