CoFe2O4/multiwall carbon nanotubes (MWCNTs) composite nanofibers were produced by electrospinning a dispersion of MWCNTs in a solution of polyvinylpyrrolidone, iron(III) nitrate nonahydrate, cobalt (II) acetate tetrahydrate, absolute ethanol and H2O. Microstructure was examined by scanning electron microscopy (SEM) and high resolution transmission electron microscopy (HR-TEM). Thermal behaviour was studied by thermogravimetry and differential thermal analysis (TG-DTA) and phase analysis of calcined fibers was performed by X-ray diffraction (XRD). Upon thermal treatment at 450 degrees C defect-free, randomly oriented composite fibers having a mean diameter of 60 +/- 10 nm were obtained. The results show that the presence of MWCNTs does not affect the spinel cubic phase formation. (C) 2010 Elsevier B.V. All rights reserved.