Despite advances in diagnostic and therapeutic technologies for cardiovascular diseases (CVDs), it remains a leading cause of mortality and morbidity worldwide. This underscores the urgency for innovative approaches aiming at early and precise detection and treatment of CVDs to reduce the disease burden. Iron oxide nanoparticles (IONPs), with their unique magnetism and bioproperties, have shown great potential in this regard. In this review, we will begin with a brief overview of the synthesis and properties of IONPs. We will then focus on the latest applications of IONPs in CVDs, including diagnosis and treatment. The use of IONPs in the integration of diagnosis and treatment for CVDs is a promising field, and will be addressed in a separate section. The translational potential and challenges of IONPs will also be discussed. In conclusion, ongoing research and development of IONP-based strategies are highly likely to address current challenges effectively, and offer more personalized and efficient options for the diagnosis and treatment of CVDs.