Abstract: This study aimed to evaluate the effects of feeding lactating buffaloes on different dietary protein sources on amino acids profile of milk and milk urea nitrogen. Eight lactating Egyptian buffaloes in second lactation season weighed 730±32 kg in average were used after 8 weeks after calving, the animals arranged in three swing over design. Tested sources protein were Soybean Meal (SBM), Cotton Seed Meal (CSM) and Sunflower Meal (SFM). Rations differed in source of protein supplement: Ration one (R1) contained three meals, ration two (R2) contained soybean meal and cottonseed meal; ration three (R3) contained soybean meal and sunflower meal and ration four (R4) contained soybean meal alone. Result indicated that SBM had higher essential, non-essential amino acids values. Also, total Non-Essential Amino Acids (NEAA) were numerically higher for SBM (22.29) vs. CSM (20.46) and SFM (14.78). The ratio EAA/NEAA value in SFM (0.91) was higher than soybean meal (0.89) and cotton seed meal (0.81). Ration three had the highest in most of essential amino acids, non-essential amino acids and total EAA (30.39). Total NEAA value was the highest in R3 (33.52) compared with other rations. Ration one recorded the highest values in most of essential, non-essential amino acids and total EAA and ratio of EAA/NEAA in milk compared with other experimental rations. Whereas, R4 had the lowest ratio of EAA/NEAA in milk. Milk urea nitrogen was significantly lower with R1 (11.67) compared with R4 which recorded highest value (12.97) followed by R2 (12.78) and R3 (11.90). It could be concluded that feeding lactating buffaloes on more than one source of protein in its rations had a positive effect on amino acids profile in milk and decrease milk urea nitrogen (MUN) level.