Three experiments were conducted to evaluate effects of estrus and GnRH at time of insemination on LH and progesterone. Cows were (n=5) or were not (n=5; control) given GnRH 12 hours after initiation of estrus (experiment-1). Cows were given GnRH 10 to 11 (n=10) or 14 to 15 hours (n=10) after initiation of estrus (experiment-2). Cows did (n=5) or did not (n=5) initiate estrus before GnRH (experiment-3). GnRH tended to increase LH release 12 to 18 hours after estrus, tended to reduce LH pulses 26 to 32 hours after estrus, increased progesterone, and caused an earlier rise in progesterone. GnRH 10 to 11 hours after estrus increased progesterone and tended to cause an earlier rise in progesterone compared to GnRH 14 to 15 hours after estrus. Initiation of estrus before GnRH did not influence LH or rise in progesterone but increased progesterone compared to cows which did not initiate estrus.