The aim of this study was to estimate the carrying capacity  and its trophic status of Saguling Reservoir, West Java, Indonesia, where cage farms for the intensive culture of common carp are located. For this purpose phosphorus budget model was applied in a series of steps and the carrying capacity of the lake was found to be 34,279.1  tonnes per year. This estimated value was lowest than the present production level of the lake. It seems possible to orientate the fish culture in cages in inland waters by using the phosphorus budget model recommended in this study. Based on the fertility classification of TRIX Index , the productivity of the Saguling Reservoir  has reached eutrophic level.