The data for the Present investigation were analyzed from records (1999-2008) of Magra Sheep research fl ock maintained with CSWRI, ARC, Bikaner. Records of 1638 Magra lambs for growth performance was analyzed to assess the impact genetic group, period of birth, sex and parity. The overall least-squares means were observed for average daily gain in body weight during 0-3, 3-6, 6-12 and 0-12 months of age were estimated as 124.20 ± 1.135, 78.88 ± 1.792, 32.99 ± 0.895 and 68.52 ± 0.745 gm/day, respectively. Effect of sire, period and sex were found highly signifi cant on weight gain. The parity had signifi cant effect on

average daily gain in body weight during 0-3 and 3-6 but non-signifi cant during 6-12 and 0-12. Regression of dam’s weight at lambing had highly signifi cant effect except average daily gain 3-6 months of age.