We report case of a subclavian artery pseudoaneurysm in a patient with type IV Ehlers-Danlos Syndrome. A 16-year-old boy underwent successful repair of a subclavian artery pseudoaneurysm that occurred after a cervical hyperextension injury. Subsequent workup included skin biopsy and fibroblast culture, which were consistent with a diagnosis of type IV Ehlers-Danlos Syndrome. This condition is a dominantly inherited connective tissue disorder, which in this patient was found to be caused by a spontaneous point mutation in the COL3A1 gene that encodes the chains of type III procollagen. The clinical, genetic, and molecular characteristics of type IV Ehlers-Danlos Syndrome are briefly reviewed.