The peripheral serum levels of progesterone and estradiol-17β were examined every other day through the normal estrous cycle and more frequently in 6 to 24 hours interval around estrus period in Korean Native goats. The goats were checked for the presence of estrus in the interval of 12 hours through the cycle and 6 hours around the estrus peaiod. They were exposed to a vasectomized buck for 30 minutes and a successful mating was identified as a standing estrus. The average levels of serum progesterone of 3 goats which showed an estrous cycle of 20 days were lower than 0.02ng/㎖ on the first day of estrus (Day 0) and increased to 0.14ng/㎖ on Day 2, 4.46ng/㎖ on Day 6 and to highest of 8.98ng/㎖ on Day 14, and then decreased to 0.26ng/㎖ on Day 18 and lower than 0.02ng/㎖ on the following Day 0. The average levels of serum estradiol-17β of these 3 goats were ranged from 23.79pg/㎖ to 28.40pg/㎖ between 6 hours before and 12 hours after the onset of estrus, and were lower than 10pg/㎖ in the other stages of estrous cycle with exceptions of higher level from some goats at the various stages.