Two buried reinforced concrete four-walled structures without floor or roof were tested, one at 200 feet and the other at 250 feet from a 1.2 kt device buried at a depth of 67 feet. The structures were instrumented to give transient load and response data. In addition, provisions were made to obtain data on permanent displacements and strains. The crater formed by the explosion was unexpectedly small, being 146 feet in radius, so that the two targets were approximately 50 and 100 feet from the edge of the crater. The structures responded primarily as rigid bodies and followed the soil motion consequently there was no structural damage. The permanent movements of the boxes were 3.8 feet and 0.5 foot, horizontally, away from the point of burst. It is concluded that buried structures of the type tested are difficult to damage structurally, unless located within or close to the edge of the crater and that, for structures outside of the crater, problems created by large earth movements and throwout might be critical for structures relatively close to the edge of the crater.