Androgen therapy has proven efficacy in treating patients with bone marrow failure who are not candidates for bone marrow transplantation. Herein, we report on a case of colonic angioectasia secondary to oxymetholone use in an adolescent patient with Hoyeraal-Hreidarsson syndrome (HHS). A 13-year-old Caucasian male with HHS characterized by cerebellar hypoplasia, developmental delay, microcephaly, esophageal strictures and myelodysplasia presented with severe hematochezia from colonic angioectasia secondary to long-term oxymetholone therapy. These vascular lesions resolved spontaneously once this anabolic steroid was discontinued. While androgen therapy is often recommended for certain anemias and myelodysplastic syndromes, clinicians should be aware of the potential complication in developing these perceived uncommon colonic angioectasias. Moreover, pediatric gastroenterologists should familiarize themselves in identifying these vascular lesions by colonoscopy, especially among the high risk groups on long-term anabolic steroid therapy.