Plants failure is one of the major problems encountered in hydro power plants. Several hydro power plants in operation are ageing, so the plants exhibit performance deterioration, part damage, high energy consumption and other operational defects. This consequently influences the operational health and safety of the plant. The present work is concerned with the review of the condition monitoring of cavitation phenomenon of hydropower plants and the selection of the most efficient technique for the detection of the phenomenon. Furthermore to accomplish this, a detailed study of the various condition monitoring techniques that are in use was done. Four methods were most prevalently used for cavitation detection among the known condition monitoring techniques: virbo-acoustic, vibration, acoustic emission analysis and visual observation. Based on the literature review carried out on hydropower failure: a pair comparison with respect to chosen parameters of performance ( i.e detectability, reliability, contact and operability) of the condition monitoring techniques was done. The selection of the most appropriate technique was made using AHP (Analytical Hierarchy process) analysis. The result from the priorities in hierarchies shows that vibro-acoustic method is the most suitable method for cavitation detection in hydropower plant.