While precipitated iron catalysts provide optimal activity and selectivity for Fischer-Tropsch (F-T) synthesis with coal-derived synthesis gas, their attrition resistance under reaction conditions has been questioned. It is well known that iron oxides undergo phase transformations during activation and reaction, leading to changes in volume, which are a primary cause of catalyst break up ('chemical attrition'). In this paper we report on attrition properties of precipitated Fe catalysts under both inert and reactive conditions in a stirred tank slurry reactor (STSR). Our results show that after 364 h of testing in the STSR, the particle size reduction due to fracture and erosion was moderate. The observed increase in fraction of particles smaller than 10 mum was small (7.8%). Catalytic performance was excellent, yielding low methane and high C-5(+) selectivities of 2.6 and 82.5%, respectively, at 78.5% single pass conversion. We conclude therefore that iron catalysts used in this study have adequate attrition resistance and desirable F-T activity and selectivity for use in conversion of coal-derived syngas to liquid fuels in the slurry bubble column reactor. (C) 2004 Elsevier B.V. All rights reserved.