Magnetoliposomes are promising candidates for the development of selective drug delivery systems in the treatment of cancer. Those nanosystems were tested as carriers of a strong chemotherapeutic agent, doxorubicin, which is used against breast cancer. Herein, the magnetic properties of hydrophobic iron oxide nanoparticles located exclusively in the lipid bilayer were used to release this drug from the magnetoliposomes. The cytotoxic activity of the nanostructures against the normal and cancer cell lines was determined on the basis of cells viability measurement after incubation with different concentrations of these nanomaterials. In the same way, the effectiveness of killing cancer cells in combination with exposure to magnetic field was also evaluated. These experiments confirmed that the nanostructures composed of liposomes and magnetic nanoparticles are not cytotoxic. However, magnetoliposomes loaded with doxorubicin were effective and selective in reducing the viability of human breast tumor cell lines. In this paper, we demonstrated the promising application of the studied magnetoliposomes as carriers of doxorubicin released under the influence of magnetic field in tumor cells.