This article reports the thermal conductivity of nanofluids experimentally. TiO2 and Al2O3 nanoparticles were suspended in base fluids (water and 20/80 by mass of an ethylene glycol-water mixture) with concentration level of 0-8 vol.%, at a temperature of 15-65 degrees C. The measurement was done by the transient hot-wire method. The results showed that thermal conductivity of nanofluids increased more with respect to the base fluid and increased with increasing concentration and temperature. When compared with predictions from existing models, thermal conductivity ratio could not be predicted by the models in terms of both concentration and temperature. Finally, a useful correlation for predicting thermal conductivity of Al2O3 and TiO2 nanofluids was presented. (C) 2012 Elsevier B.V. All rights reserved.