Fifteen patients (16 ischemic limbs) who ultimately required amputation for perinatal limb ischemia were treated at The Children's Hospital of Philadelphia and the Shriners Hospital for Crippled Children in Philadelphia between 1980 and 1993. The average birth weight of these patients was 1,870 g, and the average gestational age was 30.8 weeks. Ischemic events occurred at an average postnatal age of 5.4 weeks. The causes of the ischemia included (a) arterial thrombosis as a complication of arterial catheterization (eight patients), (b) thromboembolism resulting from a hypercoagulable state (five patients), (c) intravenous infiltrate (one patient), and (d) in utero arterial thrombosis (one patient). Amputation was required at an average postnatal age of 8.5 weeks. The final patient, with concurrent ischemia involving the right hand and left leg, had complete resolution of the ischemic hand with fibrinolytic therapy alone and required only an amputation of the lower extremity. Eleven of the 15 patients were available for follow-up (two dead, two lost to follow-up), at an average of 4.5 years. Nine of these 11 patients (six lower and three upper extremities) are functioning well in prostheses. The two remaining patients are infants who will be fitted for lower-extremity prostheses when they begin to attempt to walk.