Construction of a dam directly influence the major development of a country as population receives domestic and economic benefits from a single investment. Dam are usually constructed for supplying water for domestic, industrial and irrigation purposes, electricity generation, flood control, navigation, recreation works etc. Thus selection of most suitable site for construction of a dam is one of the important decisions to an engineer. The selection of dam site depends upon lot of factors such as topography of area, width of river, foundation conditions, water quality, erosion, environmental issues, social impacts, economic development, cost of construction etc [11,13]. Out of above mentioned factors some are quantitative and some qualitative which makes decision making a difficult task. The qualitative attributes require a significant amount of input from experts .The perception level from experts may vary person to person. Consequently it is required to use right approach so that proper judgment of site for dam selection can be done. In this study we present the methodology of generalised fuzzy logic of Prof. Lotfi Zadeh [15] for selection of most suitable location out of n alternatives for a dam to be setup. To understand the methodology, a case study is presented here.