In reinforced concrete frame buildings, slabs are usually cast monolithically with the floor beams. The currently used recommendations for the design of beam to column connections for seismic loading, however, completely ignore the presence of the slab. Even though, previous studies have shown slabs to have a significant effect on the performance of connections, it has been believed that the test data are not adequate to justify revisions of the design recommendations. In this experimental investigation, the interaction of a slab with exterior beam to column connections is studied. The experimental program consisted of tests under simulated earthquake type loading on seven large-scale exterior beam to column connections. Except for the slab width, which was varied in each specimen, the basic design and configuration of subassemblages remained the same and conformed to the current design criteria. Based on the test results, it is concluded that it may be nonconservative to ignore the slab in the design of connections. It is suggested that a certain width of the slab effectively acts as a part of the floor beam. It is also concluded that at larger levels of interstory drift, transverse beams may not be effective in confining the joint. Ignoring either of these effects can lead to nonconservative connection designs.