Deficiency of vitamin B12 (cobalamin) is a well-known cause of megaloblastic anemia. It is a reversible cause of bone marrow failure and demyelinating nervous system disorder, hence early detection and prompt treatment of vitamin B12 deficiency is essential. After diagnosing vitamin B12 deficiency, tracking down its root cause is important in individualizing the treatment approach. Helicobacter pylori-related (H. pylori) B12 deficiency presenting as pancytopenia in pediatric age groups has been reported. However, vitamin B12 deficiency presenting as retinopathy in pediatric age groups has been rarely reported in the medical literature. We herein present the case of an adolescent male with pancytopenia  and retinopathy, secondary to vitamin B12 deficiency-associated H. pylori infection.