This study aims to characterize the dairy industry wastewater and evaluate the efficiency of chemical coagulation and advanced oxidation process (AOPs) as pretreatment techniques. A composite sample was collected from diary industry plant at New Damietta City on March 2018 and characterized for some physicochemical parameters to check the pollution potential of the effluents. Due to the high content of total suspended solids, chemical coagulation/precipitation process using lime, alum/lime and alum/polyacrylamide was applied for pretreatment of the collected sample and the optimum conditions were determined. Moreover, chemical coagulation using alum/lime followed by AOPs with Fenton's reagent was also assessed. The results showed that the concentration of COD is 112000 mg/L while for BOD is 78000 mg/L. In addition, the removal percentage of oil and grease, COD, total phosphorous (TP) and total Khejdal (TKN) by Fenton's reaction after treatment with alum-lime are 86, 85, 99.35 and 99.03 %, respectively compared with that achieved by alum-lime (86.82, 73.11, 91.8 and 54.93 %, respectively). It was concluded that combining chemical coagulation/precipitation and AOPs was effective for the pretreatment of high organic load dairy wastewater.