Monodispersed oleic acid capped ceria nanoparticles were prepared by a facile one-step strategy involving thermal decomposition of a cerium oleate complex in an organic solvent with high boiling point. The nanocrystals synthesized by this relatively faster and inexpensive route have been optimized and were characterized by X-ray, infrared spectroscopy, dynamic light scattering and transmission electron microscopy. The surface-capped ceria nanoparticles exhibited excellent dispersity in conventional organic solvents and were utilized for the preparation of transformer oil based nanofluids. The suitability of the nanofluids thus obtained as heat transfer fluid was evaluated by measuring the stability of nanofluids, thermal conductivity, viscosity and particle size. The effect of particle loading and temperature on the thermal conductivity of the oil based nanofluids was studied. Oil-based nanofluids containing ceria nanoparticles showed shear-thinning behavior and produced similar to 14.6% enhancement in thermal conductivity at 50 degrees C with 0.7 vol% solid loading. (C) 2014 Elsevier B.V. All rights reserved.