One of the delayed transfusion reactions that are fatal is TA GVHD (Transfusion Associated Graft Versus Host Disease). TA incidence of GVHD in immunocompromised patients is estimated at 0.1 to 1.0% with a mortality rate of approximately 80-90% .7 Efforts irradiation of cellular blood components is currently the most efficient way and a reliable way to prevent TA-GVHD. This study aims to determine the effect of various doses of irradiation effects on red blood cells during storage.This study used a descriptive analytic design at 54 red blood cell preparations that meet the inclusion and exclusion criteria. The preparation of red blood cells were divided into 4 groups, ie the group that received 2500,3000,5000 cGy dose and control. OFT testing and potassium levels on the first day, the third and fifth storage. An increase in potassium levels was statistically significant from the first day after irradiation at all doses. There were no significant differences in red blood cell membrane resistance to all doses of irradiation during storage until the fifth day. Irradiation at doses of 2500-5000 cGy can cause increased pottasium level and does not cause changes fragility of red blood cells stored for 5 days after irradiation. The need for further research on the quality of the preparation of red blood cells during storage after irradiation as seen levels of hemolysis (hemolysis rate).