Thermal conductivity enhancements of nanodiamond particles (NDs) suspended in pure deionized (DI) with different volume fractions in the range from 0.8% to 3% have been measured. The highest observed enhancement in the thermal conductivity is 7.2% for a volume fraction of 3% at a temperature of 30 degrees C. The thermal conductivity increases by about 9.8% as the temperature rises to 50 degrees C. The new Murshed model (Murshed et al. (2009) [31]) was used to describe the heat transfer enhancement in the ND fluid. While the predicted results overestimate the experimental data, they are in agreement within the experimental errors. (C) 2010 Elsevier Ltd. All rights reserved.