The angular and velocity distributions of desorbing product CO 2 were studied in steady-state CO oxidation on Pt(110) by means of cross-correlation time-of-flight techniques. In the active region where the reaction was first order in CO, the angular distribution in the (001) plane was split into two-directional lobes collimated at +/-25 o from the surface-normal direction, indicating the CO 2 formation on inclined (111) terraces. The translational temperature was maximized at these collimation angles, reaching about 1820 K. On the other hand, in a limited range of the inhibited region, where CO retarded the reaction, CO 2 desorption sharply collimated along the surface-normal direction, suggesting CO 2 formation on flat (1x1) domains.