Dates that have been discarded are rich and inexpensive source of energy and represent a promising replacement for costly concentrates in livestock feeding. This research evaluated the impact of increasing levels of discarded dates as a substitute for yellow corn grain on intake, nutrient digestibility, and performance of lactating Barki ewes. Twenty multiparous lactating ewes (38.2 kg ± 1.18) were randomly divided into four groups (five ewes per group). The feeding trial lasted for 60 days, followed by the digestion trials. Ewes were fed a diet of concentrate feed mixture and fresh berseem clover at 70:30 on dry matter basis. Discarded dates (DD) were introduced at levels of 0, 25, 50, and 75% as a replacement for corn grain (CG) in the concentrated feed mixture (CFM) of the experimental groups (R1; control, R2, R3, and R4), respectively. Replacement of CG with DD affected the chemical composition of the ration, resulting in an increase in crude fiber content and a decrease in crude protein content. However, DD had no influence on dry matter intake, nutrient digestibility coefficients, or nutritive values (TDN, DCP, and SE). Increasing the inclusion level of DD led to a significant improvement in digestible crude fiber content and a decrease in digestible N-free extract content. Actual daily milk yield and energy corrected milk were unaffected by DD. However, ewes fed on DD at 75% numerically produced less milk yield and milk constituent yields. Also, there was no significant effect of DD on ewes' BW or lambs' average daily gain. In conclusion, discarded dates can serve as an alternative energy resource for feeding lactating ewes up to 75% of yellow corn without any adverse effect on the animals' performance.