Blood samples were drawn from uterine arteries and veins of 18 pregnant Korean native goats and from the umbilical blood vessels of each of their fetuses by laparotomy at a given stage of gestation and peripartum period, and their serum concentrations of progesterone and estradiol were measured. At 30 days of gestation the progesterone level (15.25 ng/㎖) in uterine arterial serum was similar to that in uterine venous serum. However, during 60 to 120 days of gestation the progesterone levels of uterine venous serum (6.50 to 8.43 ng/㎖) were significantly (P$lt;0.05) lower than those of uterine arterial serum. The progesterone levels in the umbilical arterial or venous serum remained lower than 3.35 ng/㎖ through the gestation period. The estradiol. concentrations in uterine venous serum during the late gestation were significantly (P$lt;0.05) higher than those in uterine arterial serum, but greatly lower than those in umbilical arterial or venous serum. These data suggest that some progesterone is utilized in placenta and estradiol is synthesized in fetoplacental unit during gestation in goats.