Arterial thromboembolism (TE) in the absence of current or recent history of a central catheter is a rare condition in newborn period. We report a case of severe lower extremities arterial TE of unclear etiology in a full-term neonate. By adding hyperbaric oxygenation to thrombolytic and antithrombotic therapy, we achieved improved perfusion of the upper leg tissues, preserving the knee and enabling below-the-knee amputation.