Abstract: Reproductive management has an important role in animal production; therefore, the objective of this study was to determine the effect of different dosages of equine chronic gonadotropin (eCG) on reproductive performance of mature Raini goats during the breeding season. One hundred Raieni goats (42±2.5 kg) were randomly allocated to five groups to receive different dosages of eCG; (0 IU as control group; and other treated groups received 350, 450, 550 and 650 IU of eCG respectively). The interval to onset of estrus was detected by using five aproned bucks. Oestrus was induced by prostaglandin and occurred 24 to 48 h after the second injection. The results showed the estrus incidence rates were not significantly different between groups (p>0.05). The pregnancy rates were 90, 90, 95, 100 and 85% in treatments and control group, respectively, with the pregnancy rate in 550 and 650 IU groups being significantly higher than the other groups (p<0.05). Twinning rates were higher in treated goats (55, 58 and 65%) than in controls (36%, p<0.05). The results of the present study show that eCG treatments increase the twinning rate in Iranian Raieni goats.