[en] The use of ionizing radiation as a food preservation technique has been recognized for many years as a means to reduce food losses, improve food safety, and extend shelf life. Furthermore, irradiation can be an effective way of reducing the incidence of food borne disease and treating a variety of potential problems in food supplies. The treatment of food with ionizing radiation is one of the most thoroughly researched techniques available to the food processing industry. In view of the afore mentioned the objective of this study were to study the effect of irradiation time and dose on Ras cheese quality, investigate the effect of irradiation after ripening on cheese quality and possibility of prolonging the shelf-life of Ras cheese, study the effect of irradiation dose on Kareish cheese quality and its shelf- life and to monitor the chemical, microbiological and sensory changes during ripening and storage of Ras and Kareish cheeses .The results of this study will be presented in three parts: Part I: Effect of irradiation dose and time on some properties of Ras cheese:Part II: Effect of irradiation on some properties during storage of ripened Ras cheese.Part III: Effect of irradiation on the quality and shelf-life of Kareish cheese: It could be concluded that irradiation caused a significant reduction of cheese ripening indices, and count of total viable,proteolytic, lipolytic bacteria and mould and yeast. Using irradiation doses of 3 and 4 kGy were able to stop the ripening factors and these safety dose were used to prevent the ripened Ras cheese irradiation of ripened Ras cheese has been prolonged the shelf-life of Ras cheese to about 32 months compared with control cheese, which showed only 18 months. The obtained results revealed that the best irradiation treatment was at the end of ripening period. Also safety irradiation of Kareish cheese has been prolonged the shelf-life of Kareish cheese to about 54 days compared with 12 days only control cheese.