The uptake of superparamagnetic Fe7C3@C nanoparticles into living cells and their behavior once inside the cell was investigated. The cells used were shown to absorb the nanoparticle aggregates over the first 30 minutes. After absorption, these aggregates moved towards the center of the cell and accumulated near the cell nucleus. No toxic effects on cell physiology were observed. In a magnetic field, the particles aligned in the cells along magnetic lines and shifted to the magnet’s side. During long-term cultivation, Fe7C3@C nanoparticle aggregates were ultimately discarded via exocytosis.