Phosphotungstic acid (PTA) was rapidly and efficiently anchored on the surface of silica coated cobalt ferrite core to obtain a new three-component CoFe2O4@SiO2-PTA nanocomposite. The resultant composite was characterized by various techniques, including FT-IR, XRD, SEM, EDX, ICP-AES, and VSM. The as-synthesized nanocomposite was examined as catalyst for N-formylation of various amines under solvent-free conditions at room temperature. Due to the presence of magnetic core in this catalyst, it can be easily separated from the reaction media by applying an external magnetic field. The isolated catalyst can be reused for at least five successive times without significant leaching or loss of its high catalytic activity. (C) 2015 Elsevier B.V. All rights reserved.