The present study explores the viability of microwave irradiation for the preparation of activated carbon (OPAC) from oil palm fiber, abundantly available from the oil palm processing industries. The activation process was performed at the microwave power of 360W and irradiation time of 5 min. The BET surface area, pore volume and average pore size of OPAC were 707.79 m(2)/g, 0.3805 m(3)/g and 22.11 angstrom, respectively. The monolayer adsorption capacity of OPAC for methylene blue was 312.5 mg/g. The finding provides a strong evidence to support the potential use of microwave heating as an alternative activation technique. (C) 2010 Elsevier B.V. All rights reserved.