In previous studies, it has been shown that the heats of adsorption at several coverages of each adsorbed CO species (linear, bridged, and threefold coordinated) on a 2.9% Pt/Al 2 O 3 catalyst can be obtained from the change in the IR band area of each adsorbed CO species with the adsorption temperature T a (in the 300-800 K range) at a constant CO partial pressure P a . In the present study, this procedure is used to reveal the eventual impact of the Pt dispersion (range 0.44-0.75) on the heats of adsorption of the linear CO species adsorbed on several Pt/Al 2 O 3 catalysts. It is shown that the Pt dispersion has no strong impact on this parameter at several coverage values.