The catalytic cracking of palm oil to liquid hydrocarbon fuels was studied in a fixed bed microreactor operated at atmospheric pressure, reaction temperature of 723 K and weight hourly space velocity (WHSV) of 2.5 h(-1) over the synthesized mesoporous molecular sieve MCM-41 materials. Mesoporous alummosilicate with Si/Al ratio of 50 was synthesized using the hydrothermal method. Different pore sizes were obtained by changing the type of template and organic directing agent (ODA) used. The synthesized materials were characterized using various analytical methods such as X-ray powder diffraction (XRD), BET surface area, inductive coupled plasma (ICP), MAS NMR, FTIR and temperature-programmed desorption (TPD). The materials exhibit a crystalline structure of MCM-41 mesoporous molecular sieves with surface area varyng from 550 to 1200 m(2)/g and an average pore size (APS) ranging from 1.8 to 2.8 nm. The synthesized MCM-41 catalysts show high activity for palm oil cracking. The conversion of palm kernel oil, lower-molecular-weigbt oil, was higher as compared to higher-molecular-weight, palm olein oil. MCM-41 materials were selective for the formation of linear hydrocarbons, particularly, C-13 when palm kernel oil was used and C-17 when palm olein oil was fed. The yield of liquid product decreased with the increase of surface area of the catalyst. The gasoline selectivity increased whereas diesel selectivity decreased with the conversion of palm oil. (C) 2003 Elsevier Science B.V All rights reserved.