In this study, it is aimed to decrease lambing interval of Karacabey Merino sheep. For this reason,in June and March, sheep were mated in the interval of 8 month. Fertility traits such as oestrus, pregnancy, parturition, lambing rate and that of twinning and litter size were 99.35, 90.25, 88.96, 1327.01, 52.55 % and 1.54 respectively in June. The values of same fertility traits were 95.17, 82.75, 78.62, 105.51, 34.21 % and 1.34 respectively in March. The body weight before mating for the sheep was found 68.03 kg in June and 61.68 kg in March. The lambing interval for the sheep was observed 9.2+/-1.11. Survival rate of lambs borned from mating in June on the 60(th) day was 91.90% and that of lambs borned from mating in March was 92.15%. Birth weight and weaning weight on the 60(th) day males were 4.32 kg. and 19.42 kg. and this weights in females were 4.07 kg. and 17.69. in same order, the values obtained in lambs borned from mating in March were 4.58 kg. and 19.90 kg. 4.31 kg, and 18.74 kg., respectively.