Urea can be fed as a source of nitrogen for rumen micro-organisms to synthesize microbial protein. It is also applied to pasture as a source of nitrogen for grass growth. Reduced fertility and embryonic loss can occur when dietary urea is in excess (McEvoy et al., 1997). Elevated plasma urea resulting from excess rumen degradable protein or dietary urea can decrease uterine pH (Elrod et al., 1993) and pregnancy rate in cows (Butler et al., 1996). The aim of this experiment was to determine the effect of dietary urea on yield and quality of embryos in superovulated donor ewes and on embryo survival (to day 34-36) in recipient ewes following embryo transfer.