In this study, various characteristics of fertility and milk yield were investigated in Chios X White Karaman crossbred (F₁ and B₁) sheep.

The study was conducted at the Research and Practice farm of the university of Fırat, on 45 F₁ and 50 B1 crossbreds at the age of 1 ½ years, mated for the first time, to examine fertility characteristics and on 38 F₁ and 41 B₁ crossbred sheep at 2 years of age to examine milk yield characteristics.

The animals in oestrous cycle were determined by addition of a teaser ram within the study population and they were then inseminated by previously selected rams. During the investigation, all the sheep were fed with 450 g concentrated feed for animal, daily in addition to pasturing. The proportions of sheep having parturition were 88.88% and 84.00% in F₁ and B₁ genotypes, respectively. Twin birth rate, average lamb number at each parturition and the proportion of lamb number at weaning were calculated as 45% and 19.04% (P<0.01); 1.45 and 1.23 (P<0.05); and 93.33% and 86.00% in F₁ and B₁ groups, respectively.

The values of daily milk yield were 724.30, 710.45 and 285.70 g in F₁ crossbreds and 520.40, 550.20 and 205.65 g in B1 crossbreds on the 30^th, 90^th and 150^th days, respectively. Milk fat rate, and lactation period in F₁ and B₁ crossbreds were 5.22%, 6.17 days and 148.74 and 146.35 days, respectively. The lactation milk yield in genotypes were found as 94.43 and 58.46 kg (P<0.01).