Composite materials composed of MCM-41/Beta were synthesized using two methods:(1) seeding method, and (2) two-step crystallization process. Powder XRD showed the existence of well-structured microphase zeolite Beta and mesophase MCM-41 in the composite materials. The performance of the composite material as a catalyst was investigated in the cracking of waste used palm oil for the production of liquid hydrocarbons and its activity was compared with the catalytic activity of a physical mixture of zeolite Beta and MCM-41. The composite material synthesized via seeding method gave a better performance in terms of conversion and yield of liquid fuel gasoline fraction compared to composite material obtained from two-step crystallization process and physical mixing. The composite material was found to be more selective for liquid fuel gasoline fraction enriched with more olefins compared to zeolite Beta or MCM-41 catalyst alone. (C) 2004 Elsevier B.V. All rights reserved.