A total number of 20 Ossimi ewes were used in this experiment. Ewes were randomly assigned to four equal groups, two groups (G1& G2) suckled single and two groups (G3 & G4) suckled twins. Ewes in the first and second group were fed on basal diet (control-single) and on basal diet+100mg daily Nigella Sativa seeds/head for G2. Ewes in the third (G3) and fourth (G4) groups were fed on basal twin diet (control-twins) and on basal twin diet +100mg daily Nigella Sativa seeds/head for G4. Daily milk yield was measured for each ewe starting from the fifth day post lambing until weaning at 3 months. Milk samples were taken weekly throughout the suckling period from all tested ewes. The samples were taken in the morning and afternoon and then both samples were mixed together for chemical analysis. Milk energy values were calculated. The results of this experiment indicated that milk yield had insignificant differences at first and second weeks of the experiment but from the third to the twelfths week the difference among groups recorded highly significant (P<0.01) increase for G2 and G4 compared to G1 (control/single) and G3 (control/twins) groups. The results revealed that the ewes reached maximum yield (peak) at the third and fourth week of lactation and decreased after that. In addition, milk yield was significantly (P<0.01) higher for ewes suckling twins than those suckling single lambs. Dietary supplementation of Nigella Sativa seeds significantly (P<0.01) increased milk fat percentage, protein percentage and milk energy. Also, fat percentage, protein percentage and milk energy gradually increased with the advance of lactation until the end of the lactation period.