A study was conducted to investigate genetic and non-genetic factors influencing reproductive and growth performance of Menz and Awassi x Menz (A x M) crossbred sheep under semi-intensive conditions at Amed Guya Sheep and Forage Seed Multiplication Center. Growth records of lambs of Menz (n = 2711), 50% A x M (n = 2207) and 75% A x M crossbred (n = 889), and corresponding reproductive recordsfrom Menz ewes (n = 2996) and 50% A x M crossbred ewes (n =1445) as well as lamb mortality data (n = 510) collected from 1993 to 2009 were analysed. Reproductive performance was estimated based on: fecundity, fertility rate, lambing rate and weaning rate. Fixed effects fitted were year of mating or lambing, season of mating or lambing and breed (Ram and Ewe) for reproductive performance evaluation. Data structure in the present study did not permit to determine the parity of reproduction traits. Data were analyzed using GLM procedures of SAS (2002). There was a significant (P < 0.05) effect of mating year on fecundity. Lambing rate andfertility rate was significantly (P < 0.01) affected by ram breed and mating year. Ram breed (P < 0.05) and lambing year (P < 0.000 1) had a significant effect on weaning rate. The least squares means for reproductive traits were 1.02, 62.78%, 61.83% and 89. 90% for fecundity, lambing rate, fertility rate, weaning rate, respectively. Reproductive trait (fecundity: 1.00 versus 1. 02; lambing rate: 70.40% versus 63. 05%; fertility rate: 70.22% versus 62.04%) and weaning rates (94.45% versus 91.09%) for 50% A x M and pure Menz ewes, respectively, were not significantly different. The overall mortality rate was 11.13%. Growth performance was estimated based on birth weight (BW), Average Daily Gain (ADG) and weaning weight at 90-day (WW), respectively. Fixed effects used were year, parity, breed, season, birth type and sex of lamb for growth. The genotype of lamb, sex and birth year were significant sources of variation for birth weight, ADG and weaning weight. Birth season significantly affected the birth weight (P < 0.01) and ADG (P< 0.001). Parity had a significant (P < 0.0001) influence on the ADG and weaning weight. Type of birth, however, only significantly (P < 0.0001) affected birth weight. Least squares means for BW (kg), ADC (g/day) and WW (kg) were: 2.70, 95.44 and 11.36, respectively. Lambs born in the main rainy season were heavier (P < 0.01) than those born in the dry and short rainy season at birth, while lambs born in the dry and short rainy season recorded a higher (P < 0.001) pre-weaning ADG than main rainy season born lambs. Male lambs were heavier (P < 0.0001) than female lambs at birth, weaning and pre-weaning daily gain by 0.07 kg, 0.2 kg and 3.72 g/day, respectively, while lambs born as singles were heavier (P < 0.0001) than lambs born as twins at birth by 0.71 kg. Results also revealed A x M crossbred lambs were notably heavier and grew faster than Menz through the period under investigation. However, Menz lambs had a higher survival rate than the lambs born from 50% & 75% A x M lambs. It is concluded that the effects some of genetic and non-genetic factors on both growth and reproductive traits considered were significant and hence need to be considered in sheep breed improvement program.