This study aimed to investigate the impact of feeding by different corn silage (CS) proportions on ewes milk yield and fatty acids composition. Twenty-one lactating Assaf ewes were divided into 3 groups (7 ewes each). The following dietary treatments based on increasing the proportion of CS in the total mixed ratio (TMR) were tested; (1) 47 % AH (0 % CS in the TMR) correspond to 0 % CS, (2) 23.5 % AH (23.5 % CS in the TMR) correspond to 50 % CS, and (3) 0 % AH (47 % CS in the TMR) correspond to 100 % CS. After 8 weeks of feeding, the type of diet had no significant effect on milk yield and solid; however, it significantly affects the milk fat. The levels of C8:0 and C14:0 were not affected by different silage levels. While the C10:0 and C12:0 significantly increased when fed on a 100 % CS diet. However, a significantly lower level of C16:0 (33.22 %) was observed in the 100 % CS compared to feeding on silage at 50 and 0 % (40.66 and 37.98 %, respectively). Similar trend was observed for C18:0, the lowest was in 100 % CS compared with the different feeding diets (7.52, 12.69, 10.61 % for 100, 50, 0 %, respectively). Total USFA in milk were decreased (p < 0.05) by feeding 100 and 50 % CS compared to 0 % CS feeding. It can be concluded that the replacement of alfalfa with CS had some influence on milk composition, especially the fatty acids profile.