Catalyzed pyrolysis of cotton-seed cake was studied under different experimental conditions. Variables investigated were pyrolysis temperature, zeolite content and sweeping gas flow rate. Experiments were carried out isothermally. Liquids, gases and char were obtained as products of pyrolysis. The distributions of these products were determined for various contents (1, 5, 10, 20 wt.% of raw material) of zeolite at four different pyrolysis temperatures. The maximum liquid yield obtained was 30.84% at a pyrolysis temperature of 550 degrees C with a sweeping gas flow rate of 100 cm 3 min(-1) in the presence of clinoptilolite (20% based on raw material) as catalyst. The pyrolytic and catalytic liquid products were analysed in detail to determine the predominant chemical classes and the identities of the major compounds present. (c) 2005 Elsevier Ltd. All rights reserved.