BACKGROUND: Tumor necrosis factor-α (TNF-α) is involved in inducing inflammatory anemia. The potential effect of anti-TNF-α agents on anemia in inflammatory bowel diseases (IBD) is still unknown. METHODS: Analytical data and disease characteristics from 362 IBD patients [271 CD/91UC) treated with anti-TNF-α drugs were retrospectively collected. Effects on disease activity, blood markers and prevalence of anemia were assessed after 6 and 12 months of therapy. RESULTS: 29.3% patients presented anemia at baseline, and significantly reduced to 14.4% and 7.8% after 6 and 12 months of therapy, respectively. Mean ± SD Hb levels increased significantly at month 6, and this increase was sustained at 12 months. Serum markers of iron metabolism increased significantly compared to baseline, as disease activity measured by C-reactive protein (CRP) was reduced. All these effects were observed independently for CD and UC, and were independent of iron supplementation during treatment. Anemia at baseline (OR 4.09; 95%CI 1.98-8.45) and elevated CRP (OR 3.45; 95CI 1.29-9.22) were independently associated with risk of persistent anemia, as well as iron replacement during therapy (OR 4.36; 95%CI 2.07-9.16). CONCLUSIONS: Controlling disease activity with anti-TNF- α therapy significantly and independently associated with resolution of anemia in IBD, with no relevant role for iron replacement therapy.