ZnO nanophosphors prepared by a glycol mediated chemical synthesis exhibit afterglow (AG) and thermoluminescence (TL) after excitation with beta rays. These properties, which are of great interest in dose assessment of ionizing radiation fields, could be appreciably modified by Yb doping. Concentration of 1, 2 and 5% diminished the AG and TL efficiency and modified the TL glow curve shape significantly. However, the 5% Yb doping concentration reduced the AG and TL fading behavior, improving the use of ZnO:Yb (5%) as potential TL ionizing radiation dosimeter. Copyright © 2008 American Scientific Publishers All rights reserved.