Abstract: A comprehensive appraisal of safety of a dam should consider all factors that contribute to the hazard potential of the structure and its appurtenances. A numerical dam hazard potential index may be developed for purpose of comparison. From the practical viewpoint appraisal methodology should consist of a“check for the weakest link”. Essential steps in a comprehensive appraisal program for safety of an old dam are discussed in this paper. The importance of adequate factors of safety in the hydrological aspects of design of a dam are also discussed and illustrated by actual case histories.