The performance of a reverse osmosis desalination plant revolves around the performance of the membranes. In theory, there are several membrane manufacturers' guidelines of how to maintain membranes and prolong their life while achieving the expected seawater treatment requirements. Combining theory with membrane operational experience allows the development of basic rules which help to make more appropriate and early decisions in order to sustain the required membrane performance. This paper describes the development of an overall strategy of membrane management bringing together three essential membrane activities in one single time based system: (a) membrane performance monitoring, (b) membrane cleaning, and (c) membrane replacement. The development of an overall membrane management system has been derived over a 4-year operation of the Larnaca desalination plant in Cyprus. The plant meets all its contractual obligations, including the all-important energy consumption criterion.