Treatment of dairy wastewater (DWW) is essential for disposal purposes and for reclaiming pure water that is usable in many water consuming areas. As a result, the development of state-of-art techniques is vital in treating this kind of wastewater, one of which is membrane distillation (MD). MD has been proposed for the treatment of DWW as it was proven to have a lot of attractive aspects. Therefore, MD in direct contact configuration (DCMD), was employed in this study to investigate its efficiency in treating DWW. In this work, the DWW samples were provided by Mazoon Dairy Industry, Oman. The samples were pretreated using 5-micron PP cartridge filter for suspended solids removal. Additionally, polytetrafluoroethylene (PTFE) and polypropylene (PP) membranes with a pore size of 0.2 µm and water contact angles of 137° and 128°, respectively, were utilized in this study. MD experiments were conducted for a duration of 7 hours at different feed temperatures (i.e., 40, 50 and 60°C) whereas the temperature of the permeate side was kept constant at 23°C. Experiments using ultrapure water (UPW) were conducted to quantify the maximum flux values achieved by both membranes. The flux was found to be 17.3 kg/m2 .h at 40°C, 28.1 kg/m2 .h at 50°C, and around 41.7 kg/m2 .h at 60°C for PTFE membrane, whereas in PP membrane it was 21.7 kg/m2 . h at 50°C. Furthermore, synthetic saltwater (SW) [1250ppm] tests were done to mimic the salts present in DWW and study their effect on MD performance. It was observed that the flux has reduced slightly in comparison with UPW flux. This reduction in flux is justified by water vapor pressure reduction due to the presence of salt, which reduced the amount of vapor passing through the membrane pores. On the contrary, using DWW as feed have led to significant flux deterioration as the feed temperature increased, due to the reduction in the effective area available for evaporation. This is caused by dairy components accumulation at the membrane surface. In terms of rejection using PTFE membrane, a rejection of 99.9%, 90.2%, 96.2%, and 99.8% were obtained for TDS, BOD, COD, and TOC respectively. In terms of volatile components rejection, it was found that D limonene, the dominant volatile component in DWW, was 100% rejected by MD. However, traces of volatile fatty acids such as acetic acid, propionic acid, and butyric acid were found in the permeate. After investigation of rejection factors and flux values at all the three investigated temperatures, it was concluded that 50°C is the optimum temperature. Therefore, PP membrane experimentations were held at that temperature. The maximum flux achieved by PP membrane was 21.76 kg/m2 .h. Using PP membrane accomplished a rejection of 98.4%, 91.2%, 97.5%, and 99.8 % for TDS, BOD, COD, and TOC respectively. D-limonene was 100% rejected by PP membrane as well. In addition, results obtained from SEM/EDS showed that there were dairy compounds deposited at the membrane surface. EDS analysis revealed several various elements at the membrane's surface resulted from dairy composites such as F, C, O, Na, Ca, Al, Mg, Fe, Cl, Si and Zn. Furthermore, new peaks were exhibited by the FTIR spectrum showing the functional groups of DWW components such as fatty acids, polysaccharides, and amides. Additionally, TGA analysis results indicated that the thermal stability of the membranes decreased with increasing the feed temperature. Taking into consideration the results obtained from this work, MD has proven to be an effective technology in DWW treatment.