In this study, florogestone acetate+eCG were administered in different sheep breeds to synchronize oestrus in breeding season. Reproductive parameters, cholesterol and progesterone levels of pregnant animals were also investigated. Fifty-nine animals (15 Akkaraman, 18 Dağlıç, 14 Awassi, 12 Chios) reared in the Research Center of Afyon Kocatepe University were used. The control group (n:29) were checked for oestrus by teaser rams and mated. The sponges containing 40 mg florogestone acetate were inserted into the vagina and kept for 14 days in the treatment group (n:30). Upon removal of the sponges. eCG was injected intramuscularly (Chios 500 IU, other breeds 600 IU). The animals were checked lor oestrus and mated at 48-52. hours after eCG injection. The blood samples were collected from the animals to deietmine the cholesterol and progesterone levels before Ihe insemination (two times), on Day 45, 90 and 135 of the pregnancy and on Day 10 after parturition. The oestrus occurrences were 100.0% in both control and treatment groups. The differences in pregnancy rate among different breeds were not significant, however the lambing rate in Chios was significantly high in both groups (p<0.05). Cholesterol levels were 67.15±2.35-72.26±2.50 mg/dl prior to pregnancy, 64,86±1.63mg/dl on Day 45, 50.07z2.07mg/dl on Day 90, 62.69+1.63mg/dl on Day 135 of gestation and 46.74+1.06mg/dl on Day 10 after parturition. Progesterone concentration was observed to be higher in Chios than that of the others before the insemination. The differences in the progesterone levels appeared to be significant in the later stage of pregnancy (p<0.05). There was a positive correlation between progesterone and cholesterol, except in the second stage before the insemination. A poaitivecorrelatton was alsa detected between the number of lambs and choleslerol-progesterone levels. it was concluded that the progesterone+eCG appncauon during oestrus season had no advanlage in diHerent sheep breeds. Cholesterol corcentranon was not effectedby Ihe gestation period and the number of lambs. Progesterone levels were significantly differenl at every stage of gestation. The results aıso snowed that Ihe posınve coııelalion between cholesterol and progesterone levels may not give any idea about pregnancy stage and number of lambs because of the many other taeters effecting cholesterol concenlration.