There has been an increasing interest in recent years in catalytic cracking of mixed C4 alkene to produce ethylene and propylene over zeolite catalysts. Among numerous catalysts which are used in such a process, the zeolite ZSM-23 showed distinctive potential. In this report, pure and well-crystallized ZSM-23 (MTT) catalyst was synthesized under static hydrothermal conditions using pyrrolidine as template. The product obtained was characterized by powder X-ray diffraction (XRD), ICP atom emission, scanning electron microscopy (SEM), thermal analysis (TGA-DTA) and FTIR of adsorbed pyridine. The ZSM-23 was used as catalyst in mixed C4 alkene cracking and showed very high catalytic activity and yields of ethylene and propylene. The effects of reaction temperature, WHSV crystallite size, pore size and Si/Al ratio on the catalytic activity were also studied in detail. (C) 2004 Elsevier B.V. All rights reserved.