OBJECTIVE: To report on the occurrence of in utero acquired limb ischemia in two referral institutions managing monochorionic (MC) twins with and without twin-to-twin transfusion syndrome (TTTS) and estimate its prevalence. METHODS: All MC twin pregnancies assessed at two referral units between 2002 and 2007 were retrospectively reviewed for the presence of in utero acquired limb ischemia. RESULTS: A total of 391 MC twin pairs with TTTS and 384 MC twin pairs without TTTS were included. The prevalence of in utero acquired limb ischemia in MC twin pairs was 0.52% (4/775). An ischemic defect of the right upper limb was detected in two recipient twins in the TTTS group, whereas an ischemic defect of the right lower limb was found in two infants in the group without TTTS. CONCLUSION: In utero acquired limb ischemia may occur in MC twins with TTTS and without TTTS. In TTTS, we only observed this event in recipient twins. In our experience, its prevalence was higher than in the general population. Copyright (c) 2008 John Wiley & Sons, Ltd.