Abstract: The aim of this study was to investigate the effects of sheep breed, parity and post-mating nutrition on embryo wastage in early pregnancy. The experimental design was completely randomized and the groups of ewes arranged factorially (2x2x3) according to the breed (Rahmani or Barki), parity of the ewes (nulliparous or parous) and post-mating nutritional regimen through the first 45 days of pregnancy (70% of the maintenance requirements, or 130% of the maintenance requirements). Rahmani ewes recorded significantly higher estimates than Barki ewes in crown-rump length at days 25 and 45 of pregnancy. At day 45 of pregnancy, both parity and post-mating nutrition significantly affected body weight, body condition score and backfat thickness of ewes. A clear reduction in pregnancy rate estimates, at day 45 of pregnancy, were recorded in the under- and the over-nourished ewes compared to the controls. A double-fold of embryonic wastage was recorded in the over-nourished ewes and three folds in the under-nourished ones at day 45 of pregnancy in comparison with the medium-nourished ewes. Crown-rump length of embryos was higher in the over-nourished animals. The under-nourished ewes had higher P4 level at days 25 and 45 of pregnancy, while the over-nourished ones recorded lower estimates than the control ewes. Therefore, it is important to control the feeding allowance of ewes in early pregnancy to be around the maintenance requirements to get a considerable proportion of viable embryos.