Novel type of the catalytic material: a permeable composite monolith (PCM) is studied in the Fischer-Tropsch synthesis (FFS) at 2.1 MPa. Due to highly intense mass transfer and high density of an active component, it was shown to provide steadily the process productivity of ca. 100-200 mg/(h cm(3)) of reactor volume at 483 K. At that the selectivity of the process over PCM is maintained at the highest level (alpha = 0.84; the olefin fraction in the C-3-C-4 fraction above 50%). At the effective mode of the PCM particle operation, the effectiveness factor of ca. 70% is achieved. (C) 2003 Elsevier Science B.V. All rights reserved.