We here present two very rare cases of high median nerve palsy caused by pseudoaneurysm after brachial catheterization. A 71-yearold woman developed high median nerve palsy 2 weeks after brachial catheterization. She underwent pseudoaneurysm resection together with neurolysis 4 months after the onset of palsy. Surgical findings suggested that her palsy was caused by both severe compression by pseudoaneurysm and adhesion following hematoma after catheterization. Five months after the surgery, she only had slight sensory disturbance. A 48-year-old lady developed high median nerve palsy 1 week after the catheterization. Simple pseudoaneurysm resection was performed 2 weeks after the catheterization. Neurolysis was not performed. Seven months after the surgery, she still had severe sensory disturbance. Our cases suggested importance of secured astriction after catheterization, and recommended surgical procedure for this condition is combination of pseudoaneurysm resection and neurolysis by hand surgeons.