The case records of all infants under the age of 6 months who underwent surgery for acute arterial thrombosis between January 1980 and September 1991 were reviewed. Seven infants (nine ischemic limbs) were identified and ranged in age from 5 days to 5 1/2 months (mean 2.4 months); all weighed less than 5 kg (mean 3.9 kg). The cause in each case was iatrogenic. Diagnosis was based on the presence of a cool, mottled extremity associated with the absence of insonated peripheral arterial Doppler signals. Treatment included aortoiliac thrombectomy (n = 2), femoral artery thrombectomy with primary closure (n = 4), femoral artery thrombectomy with autogenous saphenous vein patch (n = 1), and axillary artery thrombectomy with end-to-end anastomosis (n = 1). Palpable pulses were restored in five (56%) of nine limbs and Doppler signals in the remaining limbs. There were no instances of limb loss. Excluding aortoiliac thrombectomy, palpable peripheral pulses were reestablished in only 40% of extremities. Thrombectomy is a safe and simple procedure in even the very youngest of patients with arterial insufficiency, but surgical optimism should be tempered by frequent inability to achieve full and durable success.