The objective of this study was to estimate the amount of water loss from 6 Egyptian lakes and Naser reservoir and compare it with supplied water in Egypt. The total surface areas of the 6 lakes and Nasser reservoir were found to be 2254.2 km² and 6276 km², respectively; they are currently in operation. Total evaporative loss from water surfaces was 17.085 x 10⁹ m³ per year, of which 3.757 x 10⁹ m³ is from lakes and 13.328 x 10⁹ m³ from the Naser reservoir. This amount of water loss through evaporation is greater than the 9.6 x 10⁹ m³ of the groundwater, and it is greater than the amount of the re-use of agriculture drainage water (13.5 x 10⁹ m³/year), rainfall (1.3 x 10⁹ m³) and the destination of seawater (0.35 x 10⁹ m³).