In this work, the change of properties of empty fruit bunches (EFB), mesocarp fiber (PMF) and kernel shell (PKS) of oil palm when subjected to torrefaction process is reported. The properties include CHNS content, gross calorific value (GCV), mass and energy yields. These oil palm residues are torrefied at 200, 220 and 240, 260, 280 and 300 degrees C, respectively for duration of 2 h. In general, it has been found that the GCV and carbon content increase with the increase of torrefaction temperature but the O/C ratio, H and O content decrease for all residues. Also, we have shown that there are linear relationships between the mass loss with GCV and C content suggesting that it can be used as an indicator to monitor the severity of torrefaction process on these oil palm residues. (C) 2013 Elsevier Ltd. All rights reserved.