Sheep growers in Iran who raise breeds with light body weight, most often are interested to use rams of the heavier breeds to inseminate their ewes in order to obtain heavier lambs at sale. However, this practice may or may not be supported with enough scientific evaluations, on which only the results of very few studies are available (Kiyanzad, 2001; Farid, 1991; Makarechian et al 1978). The objective of this work was to declare the growth and feedlot performances of crossbred lambs, resulted from Afshari, Moghani and Shal (three heavy breeds) rams and Varamini (a light breed) ewes. The perfrormance of pure Varamini lambs was also adopted as a comparison benchmark.