The use of magnetic nanoparticles (MNPs) is a promising technique for future advances in biomedical applications. This idea is supported by the availability of MNPs that can target specific cell components, the variety of shapes of MNPs and the possibility of finely controlling the applied magnetic forces. To examine this opportunity, here we review the current developments in the use of MNPs to mechanically stimulate cells and, specifically, the cell mechanotransduction systems. We analyze the cell components that may act as mechanosensors and their effect on cell fate and we focus on the promising possibilities of controlling stem-cell differentiation, inducing cancer-cell death and treating nervous-system diseases.