Recently developed hexagonal boron nitride (hBN) containing nanofluids are relatively new class of materials, and increase in their thermal conductivity with respect to base fluid is relatively higher than that of viscosity. This study focuses on convective heat transfer characteristics of hBN-water nanofluids, and thermally developing laminar forced convection of hBN nanofluids in a horizontal copper pipe, subjected to constant heat flux boundary condition, is investigated experimentally. hBN-water nanofluids, with a particle volume concentration range of 0.1-1% are considered for a Reynolds numbers' range of 800-1700. Measured thermophysical properties of hBN-water based nanofluids are used in predicting the heat transfer behavior based on measurements. It is observed that the enhancement in the convective heat transfer coefficient of hBN-water nanofluids is proportional to the observed thermal conductivity enhancement. Therefore, there is no abnormal enhancement in the measured Nusselt number, and measured values are in good agreement with predictions by standard laminar thermally developing flow correlations. (C) 2017 Elsevier Ltd. All rights reserved.