Four lactating buffalos with an average weight of 515 kg were randomly assigned to four experimental groups in a 4 × 4 Latin Square design experiment with repeated measures in time for 16 weeks (4 treatments and four experimental periods).Each group received one of the following four dietary treatments:1- Control ration(fed a basal diet of berseem clover and concentrates (60:40 DM basis), 2- flax group (fed the control diet +2% flaxseed oil),  3- soya group (fed the control diet +2% soybean oil) and 4- flax & soya group (fed the control diet +2% soybean oil plus flaxseed oil (1:1 v/v)). The results showed that the supplementation of buffaloes' diets with soybean, flaxseed oils or mix-oils had no negative effects on total dry matter intake. Concerning blood serum parameters, flax group had highest values of serum TP, albumin, glucose, triglycerides, cholesterol (HDL, LDL), creatinine, and GOT, while soybean oil treated group recorded the highest values of serum cholesterol, AG ratio, (GPT) and urea-N followed by flax group then flax+soya group. The flax group recorded the highest values of daily milk yield (8.55 kg/h/d), F C M yield (12.71 kg/h/d) and fat content (7.24%), while soya oil treatment recorded the highest values of total solids (19.10%), solids not fat (12.04%), protein (4.91%), lactose (6.16%) and ash content (1%). Control group revealed the lowest values of total solids (17.73%), fat content (6.64%), solids not fat (11.09%), lactose (5.71%). Flaxseed group recorded the highest values of all milk constituents yield except total protein yield followed by soya group, then flax + soya group, while control group recorded the lowest values. Fatty acids in milk showed that C_16:0 was higher in control diet than treated diets. Stearic acid (C_18:0), C_18:4, C_20:0 and C_20:1 revealed higher values with treated diets than control. At the same time, treatment with soya or mixture of soya and flax oil showed higher values for C_18:2 than control or flax treated animals. It could be concluded that adding vegetable oils to buffaloes diet enhanced milk yield and fat content and C_18:0, C_18:4, C_20:0 and C_20:1, however, treatment with soya or mixture of soya and flax oil showed higher values for C_18:2 than control or flax treated animals.