Experimental and numerical studies are performed to investigate the heat transfer characteristics of two-dimensional forced convection from plates with transverse groove-fins, either protruded or flush-mounted to the stream. The studies are made for four aspect ratios and five different Reynolds numbers. A wind tunnel is used together with a Mach-Zehnder interferometer to measure the temperature distribution. Numerical analysis is carried out to compare the heat transfer characteristics with the experimental results and to investigate the flow patterns. Good agreement between the two studies is found. The numerical method is employed as the tool of parametric study. The cases of protruded mounting and flush-mounting are compared with each other. Local Nusselt number and total heat transfer rate are calculated for all cases and correlations of average Nusselt number are presented as functions of the Reynolds and the Prandtl numbers. Protruded grooves yield much larger heat transfer rate than the flush-mounted ones owing to deeper flow penetration into the groove after the recirculation cell over the leading edge. Total heat transfer rate from the flush-mounted grooves is not so greater than that from a flat plate; sometimes, it is even smaller. Grooved fins with protruded mounting are recommended for heat transfer enhancement and the total length is recommended not to exceed the reattachment length significantly. The derived correlations and physical considerations may be used when designing grooved plates to enhance or suppress heat transfer.