Successful use of ion-exchange chromatographic technique using nano-zirconia (t-ZrO2), to concentrate I-125 solution obtained from wet chemical distillation method to levels required for preparation of I-125 brachytherapy sources, is reported. A careful scrutiny of the sorption parameters of t-ZrO2 was carried out and implemented to arrive at conditions resulting in optimum retention of I-125 from its solution of low radioactive concentration on a tiny column containing t-ZrO2, followed by its elution in a small volume of eluent. The developed procedure was validated using samples containing varying amounts of I-125 activity in the feed and the concentration factors (CF) of I-125>5 could be obtained. The overall recovery of I-125 was >90% with appropriate radiochemical purity. The compatibility of the product in the preparation of I-125 brachytherapy sources was found to be satisfactory.