This work highlights boosting the tumor targeting efficiency of epirubicin through loading on a new radio- nanosystem, based on the effective role of silver nanoparticles (AgNPs). Accordingly, PEGylated silver nano- particles (PEG/AgNPs) were prepared in a size of 20.2 ± 0.1 nm. Additionally, epirubicin was loaded on PEG/ AgNPs with a loading efficiency of 63 ± 3 %. Furthermore, both of PEG/AgNPs and EPI/PEG/AgNPs were radiolabeled with 131I isotope with radiolabeling yields of 85 ± 0.2 % and 90.3 ± 1 %, respectively. The in-vivo distribution of 131I-PEG/AgNPs and 131I-EPI/PEG/AgNPs were examined in healthy and tumor bearing mice models. Excitingly, 131I-EPI/PEG/AgNPs revealed a reticuloendothelial system (RES) avoidance and prolonged circulating time. In addition, 131I-EPI/PEG/AgNPs showed fast targeting of tumor site by 25.1 ± 0.1 %ID/g within 0.5 h after intravenous injection. Subsequently, the outcomes provided 131I-EPI/PEG/AgNPs as a new potential system for enhancement of tumor targeting and theranosis (therapy and/or imaging).