One hundred Karakul ewes were divided according to age in two groups of 50 ewes each. Group 1 were stimulated by teaser rams, while Group 2 served as the controls. The body masses of the ewes in both groups were kept constant by feeding them a maintenance ration consisting of a 70:30 ratio of lucerne and maize. Three teaser rams were joined with the ewes in Group 1 for a period of 17 days. Laparotomies were performed on 20 ewes of each group before, and 10 days after, joining with teaser rams. From this it was concluded that silent ovulations occurred in 40% of the ewes laparotomized. During the 25 days when the thirty ewes not laparotomized were tested for oestrus, 22 ewes (73%) in Group 1 exhibited oestrus, 19 of them (63%) within the first ten days. In the control group 12 ewes (40%) exhibited oestrus which included 6 ewes (20 %) within the first 10 days. It was noted that the remaining 8 ewes in the teaser ram group included 5 maiden ewes younger than 18 months while the remaining 18 ewes (60%) in the control group included 7 ewes younger than 18 months. It is concluded that synchronized mating in mature Karakul ewes is possible with the aid of teaser rams as much as two months before the commencement of their normal breeding season.