Although bariatric surgery fosters heightened excess weight loss values, nutritional deficiencies are prominent; one of the most common being iron deficiency anemia. The purpose is to elucidate the frequency of anemia in Roux-en-Y gastric bypass and sleeve gastrectomy subjects. A retrospective analysis was conducted, in subjects (N = 100) diagnosed with type II diabetes who were randomized into sleeve gastrectomy or Roux-en-Y gastric bypass and intensive medical therapy. Anemia was more common in female subjects who underwent sleeve gastrectomy-roughly half developed microcytosis at 24 months and thereafter. The etiology of anemia appears to be iron-related and precipitated by the female sex. Scant iron supplementation is likely causative. However, anemia of chronic inflammation cannot be discounted as being somewhat causal. Subsequently, the aggregate may have had a synergistic influence.