We present a rare case of a newborn with spontaneous, noniatrogenic arterial thromboembolism in the right brachial artery and accompanying ischemic changes to the right upper extremity, who was successfully treated with microsurgical intervention and ultrasound-guided infraclavicular brachial plexus block with a continuous infusion of ropivacaine for 48 hours. This case report highlights the emerging role of both the microsurgeon and anesthesiologist in management of spontaneous neonatal arterial thromboembolism.