Hepatocellular carcinoma (HCC) is the most common primary tumor of the liver, ranking as the second most common cause of death from cancer worldwide. Magnetic nanoparticles (MNPs) have been used so far in tumor diagnosis and treatment, demonstrating great potential and promising results. In principle, three different approaches can be used in the treatment of tumors with superparamagnetic iron oxide nanoparticles: magnetically induced hyperthermia, drug targeting and selective suppression of tumor growth. This review focuses on the use of iron oxide nanoparticles for the diagnosis and treatment of liver cancer and offers a walkthrough from the MNPs imaging applicability to further therapeutic options, including their potential flaws. The MNP unique physical and biochemical properties will be mentioned in close relationship to their subsequent effects on the human body, and, also, their toxic potential will be noted. A presentation of what barriers the MNPs should overcome to be more successful will conclude this review.