This paper mainly aims at highlighting the differences in reproductive parameters of females of a lot of Palas Merino breed crossed with the Merino Palas breed male (group I) and a lot of Palas Merino females crossed with males of breed Ile de France (group II). Research has been conducted in a trading company in Vaslui county, on a herd of 600 female heads. The results showed that reproductive parameters of Merino sheep breed group crossed with rams of the breed Ile de France (group II) where higher compared to the Merino sheep breed group crossed with Merino rams (group I), given that environmental conditions were identical for two lots. So, the index of fecundity determinate had value of 92.00 %from the first batch of sheep and of 92.33 % for the second batch of sheep also The calculated prolificacy for the these two lots had values of 113.40 for the first lot and of 136.69% for the second lot. Note that two reproductive parameters analyzed a very significant difference was found in the prolificacy parameter. Of breeding parameters studied, a very significant difference was found in the prolificacy parameter.