A modified polyol process for the synthesis of cubic-shaped FeCo particles at 403 K is demonstrated. Control of the particle composition and size was achieved by varying the experimental conditions. The Fe content in the FeCo particles can be varied from 90 to 20 mol %, and the size of the cubes can be controlled to obtain particles with sizes between 300 and 35 nm (see figure). The magnetic properties of the particles closely resemble those of bulk FeCo.