Acquired α-thalassemia (α-thal) myelodysplastic syndrome (ATMDS) is a rare acquired syndrome characterized by a somatic point mutation in the ATRX gene in patients with chronic myeloid disorders. We describe the case of a 78-year-old man with myelodysplastic syndrome (MDS) and striking microcytic, hypochromic anemia. Brilliant cresyl blue supravital stain of the peripheral blood and hemoglobin (Hb) electrophoresis showed the presence of Hb H. Sequence analysis of unfractionated peripheral blood DNA identified a G>T transition at codon 524 in exon 7 of the ATRX gene. To the best of our knowledge, it is the first description of this point mutation of the ATRX gene in an ATMDS.