Pernicious anemia (PA) is an autoimmune disease characterized by atrophic gastritis and deficiency in intrinsic factor leading to impairment of vitamin B12 absorption in the ileum. Anemia is commonly found in rheumatoid arthritis (RA); however, PA is rarely found in RA. There are few reports describing patients with both conditions; none in Korea to date. We report on a case of a 46-year-old female who presented with hypesthesia and general weakness. She was previously diagnosed as seropositive RA with myelodysplastic syndrome. She had severely impaired sensation, especially for vibration and proprioception in all limbs. Subacute combined degeneration was observed on her magnetic resonance imaging and serum vitamin B12 level was very low. Further exam results were consistent with PA and her symptoms improved with cobalamin injection. This case demonstrates that PA should be considered in RA patients presenting with both central nervous system manifestations and anemia.