Ovarian stromal blood flow was measured by 133xenon-clearance technique in five women before and immediately after abdominal hysterectomy preserving the adnexae. The interval between the two measurements ranged from 35 to 76 minutes. The rate of xenon clearance was reduced by 52 to 89 percent in four of the women who were in the fertile age and by 29 percent in one postmenopausal subject. These findings indicate that acute reductions in ovarian blood flow may be responsible for the postoperative transient drop in ovarian steroid levels in peripheral plasma reported earlier.