A monolith loop catalytic membrane reactor (ML-CMR) concept for Fischer-Tropsch synthesis (FTS) was investigated by evaluating the performance of a P/Pt-Co/gamma-Al2O3 catalyst in a prototype, tubular CMR and in a tubular, fixed-bed reactor (FBR). Although experimental data demonstrate that the selectivity to paraffins and the product yield per unit catalyst mass exhibited by the P/Pt-Co/gamma-Al2O3 catalyst in the tubular CMR exceed those observed by the same catalyst in a tubular FBR, simple model calculations indicate that the ML-CMR product yield per unit reactor volume, at its present stage of development, is less than that for state-of-the-art multi-tubular fixed-bed and slurry-bubble column reactors. (c) 2005 Elsevier B.V. All rights reserved.