Since a very high heat transfer coefficient can be obtained by an impinging jet in its stagnation region, this flow geometry has been used for heating, cooling, and drying in a variety of industrial applications. This high heat transfer coefficient, however, deteriorates rapidly with the streamwise distance downstream of the stagnation line, and hence the broad downstream region is targeted by the present study on heat transfer augmentation; large-scale roughness elements of a transverse repeated-rib type are mounted over We heat transfer surface. The experimental results obtained at various jet velocities indicate efficient heat transfer augmentation.