Abstract: The application of vibroflotation to stabilization of both sand and clay foundation is described in this paper. Center-to-center spacing between stone columnes ranges from 1.5 to 2.5 meters for sand foundation. In clay foundation the stress ratio of stone columne to soil, n ranges from 3 to 6. Some case histories on sand and clay foundation are presented. These projects have been improved with great succese by vibroflotation.