Crystallographic, microstructural and magnetic properties of ZnFe2O4 nanoparticles synthesized by precipitation from non-aqueous solutions have been studied in the work. The transmission electron microscopy studies reveal particle sizes similar to 5 nm for the as-prepared particles which increase up to similar to 25 nm upon annealing at 500 degrees C. Characteristic magnetic parameters of the particles including average magnetic moment of an individual nanoparticle and effective anisotropy constant have been determined by means of the quasistatic magnetic measurements. The specific loss power which is released on the exposure of an ensemble of synthesized particles to an electromagnetic field is calculated and measured experimentally. It is shown that the particles demonstrate high heating efficiency in AC magnetic fields, which is enough for their use in medical applications. (C) 2014 Elsevier B.V. All rights reserved.