Clinical and experimental studies have shown that, in unilateral testicular torsion, some structural and hormonal changes may occur in the contralateral testis. The present study was designed to determine the effect of unilateral ovarian torsion on the blood flow in the contralateral ovary using #133Xe. Basal blood flow of the bilateral ovaries was determined in 40 prepubertal, female New Zealand rabbits. Right ovaries were then torsioned 720 degrees in all groups with the exception of the control group, where only laparotomy was performed. Bilateral ovarian blood flows were measured in the first group one hour after torsion, in the second group 8 hours after torsion, in the third group 24 hours after torsion and at the same times after laparotomy in the control group. Basal and post torsional blood flow measurements were analyzed. Contralateral ovarian blood flow was reduced after unilateral torsion in all of the groups. In the control group, there were no changes in these criteria.