Reduced fertility has been had significant impact on economic losses in dairy herds. Ovarian functional disorders are reported as an important cause of infertility in dairy cattle. Among which delayed ovulation affects about 10-15 percent of high yielding cows (Ahmad et al. 1996). Progesterone profiles at artificial insemination (AI) and on day 5 post insemination are related to conception rate. A need for adequate concentration of progesterone in early pregnancy is well established and an insufficiency of progesterone has been implicated as a cause for abnormal development of embryos and early embryonic death. Administration of GnRH during the early postpartum period has increased early ovulation, but the effect on the interval from calving to conception has been variable (Britt et al., 1974; Archbald et al., 1990). This experiment was carried out to determine the effects of GnRH injection at the time of insemination on ovulation rate, conception rate and plasma progesterone concentration on day 5 post insemination.