Iron refractory iron deficiency anemia (IRIDA) is a recently described autosomal recessive disorder caused by mutations in TMPRSS6, the gene encoding matriptase-2. Patients have inappropriately high levels of hepcidin. Hypochromic microcytic anemia refractory to oral iron and only partially responsive to parenteral iron is the hallmark of this disorder. We report six patients from three unrelated families with mutations in the TMPRSS6 gene, with three of the four identified mutations being novel. Although response to oral iron in IRIDA patients has been reported rarely before, all of our five patients receiving oral iron and our one patient supplemented with vitamin C responded to therapy at least to some extent. We think that IRIDA should be considered in the differential diagnosis of patients with findings of iron deficiency anemia responding inadequately to oral iron, particularly in countries with a high rate of consanguineous marriages like Turkey.