While designing dams, number of factors, parameters is assumed. In most of the cases, the materials are tested in laboratories and designs are based on assumptions that the same results will be met with, during actual construction. As there are always large variations in materials, their properties, construction methods and their control, the actual product defers from the original assumptions. In this project, instruments required to check the behavior and stability of dams are discussed with their necessity, use and operation. These instruments prove to be much useful in proper maintenance of dam, and hence they should be installed under the guidance of experts at appropriate places in the dam. A conclusion has been arrived that there should be close co-operation between the designers, instrumentation specialist, expert analysis and site authorities to achieve the goal of instrumentation.