Brachial artery aneurysm is rare but could be potentially both life-threatening and limb-threatening. It may lead to peripheral nerve injuries which cause disability and affect everyday function, both domestic and economic. We present a rare case of pre-menarcheal adolescent girl with Graves’ disease co-existing with radial neuropathy due to radial nerve compression by a giant brachial artery pseudoaneurysm. The patient was managed surgically with aneurysmal resection and saphenous vein graft interpositioning. Prompt diagnosis and institution of appropriate surgical repair to prevent adverse outcome was imperative.