In this paper, magnetic nanoparticles of Fe3O4 were chosen as SPE sorbents for the separation and preconcentration of trace level cadmium ions from water and food samples. Synthesized nanoparticle was characterized by SEM and TEM. Various influencing parameters on the separation and preconcentration of trace level cadmium ions such as, pH value, amount of nanoparticles, amount of diphenyl carbazone, condition of eluting solution and the effects of matrix ions were examined.