The high load of organic materials, such as sugars, carbohydrates, and fermented products is one of the main characteristics of the wastewaters of food industries. These organic compounds exist in food industry’s wastewater causes some significant pollution in the environment. The baker’s yeast is a valuable substance in bread production process. This substance increases alimental value, palatability and volume of the bread. Molass, by-product of sugar manufacturing, is mainly used as a main raw material in the yeast production. Molass contains 45–50% sugars, 15–20% nonsugar organic substances, 10–15% ash (minerals) and about 20% water. The sugars existed in the molasses are a source of carbon and energy in the yeast fermentation process. However, a major part of the nonsugar substances in the molasses are not assimilable by the yeast and then released unchanged to the wastewater. The most part of the waste in the yeast production process are contains these compounds. In addition, waste water contains other substances like the added chemicals during fermentation (e.g. antifoams, propionic acids, brine, etc.), yeast metabolites, and residual yeast cells. Since these ef?uents have high BOD and COD, they need to be treated before discharging. In this research coagulation-flocculation process and membrane separation as a new approach was used to baker’s yeast wastewater treatment. The coagulation has been done in two ways, befor membrane and during membrane filtration (inline coagulation).The first objective of this study was to investigate and enhancement of the efficiency of pre coagulation process on waste water treatment. This target followed by changing the type of coagulant (Alum, Poly Aluminium Chloride(PAC) and lime) and optimization of operating condition during coagulation. Membrane separation was performed by poly propylene (PP) and poly vinylidene flouride (PVDF).The effects of trans-membrane pressure, cross flow velocity, temperature and type of membrane were studied on permeate flux, turbidity and COD removal in membrane process. The obtained results show that the flux of permeate increase and the turbidity and COD removal efficiency decrease by trans-membrane pressure, cross flow velocity and temperature. It also observed that coagulation and settling before UF has better result than Inline coagulation.It maybe due to that flocks need more time to enlarge. In combined process(coagulation + filtration) of wastewater poly(aluminum chloride) has higher efficiency than aluminuim sulphate and lime. The combination of coagulation also has examined and was found to be quite e?ective; The combination of PAC and lime has had most efficiency and economic advantages in comparison to other combinations of coagulants. At the optimum conditions in coagulation step, the removal of turbidity and COD were 81% and 68%, respectively. At the best conditions in filtration step for PVDF membrane the permeate flux, turbidity and COD removal were 59 l/m 2 h , 99% and 74.5%, respectively. For this wastewater, using PP membrane in filtration step at best conditions leads to permeate flux, turbidity and COD removal of 81 l/m 2 h, 97% and 65%, respectively. The highestturbidityand COD removal efficiencyon the coagulation and membrane filtration processes were obtained as 99% and 91%, respectively.