Vitamin B12 is a water-soluble vitamin that acts as a coen-zyme in important enzymatic reactions in the body. Deficiency can lead to serious diseases, especially in the haematologic and nervous systems and the digestive tract. Affected people may experience weakness, fatigue, oral ulcers, papillar atrophy in the tongue, diarrhea and anemia. Severe anemia, amnesia, personality changes, dementia and depression may be seen in patients with a late diagnosis.Pancytopenia is defined as the decrease of erythrocyte, leukocyte and platelet series in blood. In the differential diagnosis of pancytopenia, there is a wide range from bone marrow diseases to infections. One of these causes is vitamin B12 deficiency. In our case report, we aimed to present a case of vitamin B 12 deficiency anemia with pancytopenia who came to our outpatient clinic with a complaint of a sore throat and cough.