Saline water containing a chlorine-containing compound in the form of free chlorine, hypochlorite, etc. which has been added as a disinfectant or antibacterial compound is desalinated by passing the saline water through a semipermeable membrane which is resistant to the chlorine. The saline water is passed through this membrane at a temperature in the range of from ambient to about 50.degree. C. and a pressure in the range of from about 1380 to about 6895 kPA (200-1000 psi). The chlorine-resistant semipermeable membrane comprises an interfacial polymerized condensation reaction product composited on a porous backing support material which has been prepared by contacting a porous support material such as polysulfone with a solution of a diaryl methylene monomer containing at least one amine radical on each aryl nucleus. The coated support material is then contacted with an organic solvent of an aromatic carboxylic acid chloride for a period of time sufficient to form an interfacial polymerized reaction product on the surface of the support material. Following this the composite is then cured at an elevated temperature to form the desired membrane.