This study was initiated to determine the production advantage of selected on-farm growth performance rams mated to Barki breeding ewes. Breeding rams selection was based on a combination of growth data and visual appraisal of muscling. Twenty-five Barki rams, representing high (H) and moderate (M) growth performance were randomly assigned to mate 180 Barki breeding ewes through out three successive breeding seasons. Data collected during this study included; ewe lambing rate, pre- and post-weaning lamb growth performance and lamb carcass merit. Results indicated that, no significant differences (P≤ .05) were found among the selected rams (H & M) on lambing rate, birth weight, weaning weight, pre weaning average daily gain and yearling weight. Meanwhile, there were a significant differences in post weaning average daily gain  among progeny sired by H rams and those sired by M rams, estimated as 12% increase in favor of H rams (86.04 gm vs. 76.75 gm), respectively. The current results demonstrated a small difference (9.25 gm/day) but economically important advantage of lambs sired by H rams compared to lambs sired by M rams. Accordingly, each marketed lamb sired by H rams will earn more revenues of approximately LE 115 than the marketed lamb sired by M rams. No significant differences (P≤ .05) were observed among carcass merit of progeny sired by H or M rams. Results concluded that ram selection based on a combination of pre- and post weaning growth performance can be used to adequately identify superior sires, as well as, using sire with superior growth traits in a commercial sheep enterprise can greatly increase lamb growth efficiency.