This contribution reviews the technique of Very Long Baseline Interferometry as a tool for high precision measurements of relative point positions and spatial baseline orientation. The geodetic and geophysical applications of these measurements are discussed in relation to the objectives of global and regional programs of Earth dynamics research. Following a description of the method and the instrumentation, the systematic errors limiting the accuracy of VLBI baseline vector determinations are discussed and the different approaches of error elimination are indicated. Some of the most interesting results recently obtained by the different groups involved in geodetic VLBI are shown.