CO hydrogenation over Re-Co bimetallic samples prepared by sol/gel technique have been investigated. Reduction of the Co2+ ions in the sol/gel samples prepared by means of ethyleneglycol (SG1) and hexyleneglycol (SG5) as gelation agent could be facilitated indicated by temperature programmed reduction (TPR), X-ray diffraction (XRD) and transmission electron microscope (TEM). The metal particle size is 2 and 20 nm, respectively. In the CO hydrogenation over the samples the C-2-C-4 fraction are formed predominantly due to high hydrogenation/chain propagation ratio. Comparing this result with that obtained over Co-Re/Al2O3 (IM) and Re-Co/NaY (IM) samples prepared by incipient wetness technique, on which the hydrogenation/chain propagation ratio is low, a large C5+ formation was observed. The nature of the active sites is discussed in terms of particle size and enhanced hydrogenation activity of rhenium. (C) 2002 Elsevier Science B.V. All rights reserved.