Arterial injuries in infants are rare and in most cases are of iatrogenic origin as a consequence of catheterization, venipuncture or arterial blood sampling. These lesions require an accurate, noninvasive clinical diagnosis and prompt exploration and reconstruction using microvascular techniques to restore perfusion and to avoid morbidity and even mortality. We present a 3-day-old infant with a brachial artery thrombosis by a white thrombus as a consequence of an unsuccessful attempt to introduce an intravascular catheter. A microvascular reconstruction was performed, with complete restoration of the blood flow. Any suspected vascular injury needs immediate clinical and diagnostic assessment in order to avoid potential life-threatening complications. Surgery is mandatory in case of extensive arterial injuries, in case of inadequate distal blood supply or in case of progressive worsening of ischemic clinical findings.