For long-term performance evaluation of radioactive waste repositories, knowledge about the radionuclides adsorption by backfill materials is required. As a part of the multi-barrier system for effective isolation of radioactive waste in a repository, alum industrial waste was evaluated to be utilized as a backfill material. In this concern, the adsorption behavior of Cs-137, Sr-90 and I-131 (as a surrogate for I-129) radionuclides on alum industrial waste (AIW) was investigated to simulate the optimum conditions under which AIW can be used as an adsorbent employing batch method using radiotracer technique. AIW was characterized using SEM, FT-IR, XRD, XRF and TGA & DTA. AIW has been successfully applied for the adsorption of some radionuclides from real radioactive waste. The results indicated that more than 90% of these radionuclides were efficiently retained onto AIW. Based on the results, it can be concluded that the AIW is an economic and efficient retaining material for environmental hazardous migration and/or leakage of some radionuclides such as I-131, Cs-137, Sr-90, Co-60, Pb-212 an d Eu-152+(154). Therefore, this study could be used as a starting point to establish and consider AIW as a backfill material in the radioactive waste disposal process. (C) 2019 Institution of Chemical Engineers. Published by Elsevier B.V. All rights reserved.