Reverse osmosis (RO) is a pressure driven membrane process which has been widely applied and recognized as the leading technology of desalination process. RO is now being used in various applications including selective separation, purification, and concentration processes. In food industry, RO is applied for concentration of fruits and vegetable juices, pre-concentration of milk and whey, RO can be applied to produce clean water for residential and industrial water supply. The application of RO as a last step of wastewater treatment for water reuse and valuable component recovery seems to be promising in wastewater reclamation.