In this study, the treatability of raw and biologically pretreated municipal wastewater (MWW) by direct contact membrane distillation (DCMD) was investigated. The treatment was performed at three various feed temperatures, 40, 50 and 60 degrees C and at constant 10 degrees C cooling water, with two hydrophobic membranes made of polytetrafluoroethylene (PTFE) and Polyvinylidene difluoride (PVDF). Both membranes had a pore size of 0.45 mu m. The conductivity, COD, alkalinity and hardness were highly rejected over 98 % while ammonium nitrogen (NH4-N) rejection efficiency was low; up to 60 %. The highest transmembrane flux (TMF) approximately 16 L/m(2). h was obtained at 60 degrees C feed temperature with PTFE membrane and pretreated solution as feed. The membranes used in this study were effective for the treatment of MWW. Checking the contact angles of the PTFE membranes after the treatment and the quality of the treated effluent showed that membrane is effective for this process.