Antithyroid drugs are usually listed among agents associated with the development of agranulocytosis, but aplastic anemia rarely follows their use. A 34year-old female was admitted to aur hospital with complaint of easy bruise. Three years before We had been diagnosed as Graves' disease and treated with propylthiouracil(PTU). Investigations were as follows' Hemoglobin 66g/L; hematocrit 19.6%; neutrophils 675/μL; platelets 13,000 /U L; corrected reticulocyte count 0.6%; Bone marrow biopsy showed severe hypocellular marrow. We reported a patient of PTU induced severe aplastic anemia with brief review of the literature.