An experimental program was undertaken to determine the out-of-plane or transverse strength ofunreinforced masonry infllls. Full-scale, single-story, single-bay reinforced concrete frames were constructed, and fllled with clay brick or concrete block masonry. Specimens were tested in the transverse direction by applying a uniform pressure (simulating wind, seismic, or explosive loads) to the surface area ofthe infills until either failure of the infill occurred or the capacity of the testing rig was reached. As the experimental phase of the program progressed, an analytical model to estimate the out-of-plane strength ofthese infllls was developed. Based on this analytical model, calibrated with the experimental results, an evaluation method was developed.