In the current study, the synthesis of a theranostic platform composed of superparamagnetic iron oxide nanoparticles (SPION)-deferasirox conjugates targeted with AS1411 DNA aptamer was reported. In this regard, SPION was amine-functionalized by (3-aminopropyl)trimethoxysilane (ATPMS), and then deferasirox was covalently conjugated onto its surface. Finally, to provide guided drug delivery to cancerous tissue, AS1411 aptamer was conjugated to the complex of SPION-deferasirox. The cellular toxicity assay on CHO, C-26 and AGS cell lines verified higher cellular toxicity of targeted complex in comparison with non-targeted one. The evaluation of in vivo tumor growth inhibitory effect in C26 tumor-bearing mice illustrated that the aptamer-targeted complex significantly enhanced the therapeutic outcome in comparison with both non-targeted complex and free drug. The diagnostic capability of the prepared platform was also evaluated implementing C26-tumor-bearing mice. Obtained data confirmed higher tumor accumulation and higher tumor residence time for targeted complex through MRI imaging due to the existence of SPION as a contrast agent in the core of the prepared complex. The prepared multimodal theranostic system provides a safe and effective platform for fighting against cancer.