The aim of this study was to evaluate the effect of diets containing dried grape marc and tomato pomace on productive performance, and milk and blood oxidative status. Twenty-four mid lactating Sarda ewes were used. One group of ewes received a total mixed ration as a control diet (CTR group) and other the same total mixed ration supplemented with 100 g/d of grape marc (GM group) or 100 g/d of tomato pomace (TP group) for 8 weeks. Daily intake, milk production, milk composition and blood parameters were affected by the inclusion of byproducts in the diet. Ewes supplemented with byproducts showed lower DM intake compared with CTR. The ewes fed GM produced more milk, protein and fat in milk than did the CTR group. The addition of TP did not affect production traits in comparison to CTR group. The blood parameters were within the physiological range for sheep in all groups, evidencing good health conditions of ewes throughout the experiment. GM group evidenced a higher antioxidant capacity measured either ferric reducing antioxidant power (FRAP) and including 2,2-azinobis (3-ethyl-benzothiazoline-6-sulfonic acid) (ABTS) in blood in comparison with the CTR. In conclusion, the GM at the inclusion level of 100 g/day, turned out to be an appropriate byproduct to improve milk yield and maintain animals health status. Research funded by Mignini-Petrini S.p.a. (Perugia, Italy) and Animal New Technology (ANT s.r.l.).