In order to reuse and concentrate the sewage, a forward osmosis using fertilizer as draw solution was applied. Sewage-1, which is the supernatant after settling for 30 minutes for the primary settling basin influent, and Sewage-2, which is the supernatant after settling for 30 minutes for the effluent, and Sewage-3, which is the filtrate filtered through a 1 μm cartridge filter for the effluent were tested. Eight draw solutions of NH4H2PO4, KCl, KNO3, NH4Cl, (NH4)2HPO4, NH4NO3, NH4HCO3, and KHCO3 were used in consideration of osmotic pressure, solubility and pH. In the case of Sewage-3, the permeate flux was almost similar to that of the discharge water of the sewage treatment plant, and was larger than that of Sewage-1 and Sewage-2. NH4H2PO4 was the smallest, and NH4NO3 was the largest in the specific reverse solute flux. NH4H2PO4 was found to be most useful for the reuse and concentration of sewage because it contains nitrogen and phosphorus, which are the major components of fertilizer, as well as low specific reverse solute flux. When NH4H2PO4 was used as the draw solution, the concentration factor after 24 hours for Sewage-3 was 1.72.