Glycated hemoglobin, measured as hemoglobin A1c (HbA1c), is an important indicator of mean glycemia and risks for diabetic complications in patients with diabetes mellitus. Reports have indicated that hemoglobin variants and elevated fetal hemoglobin (HbF) levels can interfere with some HbA1c assay methods. The normal adult red blood cell contains three forms of hemoglobin: hemoglobin A (96%), hemoglobin A2 (2% to 3%), and hemoglobin F (HbF) (<2%). Elevated HbF levels can occur in patients as a result of pathologic condi-tions such as multiple myeloma, leukemia, and hereditary persistence of fetal hemoglobin. Serum fructosamine is superior to HbA1c for assessment of glycemic control in diabetic patients with abnormal hemoglobins because its measurement is independent of hemoglobin. We present a case of a 64-year-old woman with a diagnosis of multiple myeloma and a falsely elevated hemoglobin A1c (HbA1c) due to fetal hemoglobin. A 64-year-old woman was admitted with back pain and general weakness. After careful evaluation, she was diagnosed with multiple myeloma. Her laboratory tests revealed anemia with hemoglobin of 9.2 g/dL, low albumin level of 2.8 g/dL, HbA1c 9.8% and fasting glucose 91 mg/dL. Renal and hepatic functions were normal. Laboratory results showed a discrepancy between FBG and HbA1c level. A 75 g oral glucose tolerance test showed an FBG value of 93 mg/dL, and a 2-hour glucose level of 149 mg/dL. Serum fructosamine test was within normal limits at 237 μmol/L (normal, 205 to 285 μmol/L). Hemoglobin electrophoresis revealed the presence of elevated fetal Hemoglobin with HbA of 92%, HbA1 of 2.5 and HbF of 5.5%. In situations where HbA1c levels do not correlate with blood glucose levels and fructosamine test, the presence of abnormal hemoglobins should be considered.