Bimetallic Pt-Re/Al2O3 catalysts are prepared under hydrogen atmosphere by a surface redox reaction between hydrogen adsorbed on a parent platinum/alumina catalyst and the perrhenate ion ReO4-. This reaction, called catalytic reduction, occurs only in an acidic medium, with a maximum rhenium deposition appearing as a function of the concentration of the acid solution. The preparation of bimetallic Pt-Re/Al2O3 catalysts by catalytic reduction of the rhenium salt on a highly dispersed platinum catalyst leads to bimetallic particles after activation by direct reduction under hydrogen. The calcination at 450 degrees C partially destroys the interaction between the two metals, the effect being more obvious on chloride containing samples. The activation procedure produces the reverse effect at high rhenium loading deposited on a parent catalyst of low dispersion.]