Measurement of glycated hemoglobin (HbAtc) is used for routine management of diabetic patients. Glucose linkage to HbAtc reflects mean blood glucose levels during the last 3 months before examination. Various methods for HbA1c determination show abnormal values with hemoglobin variants. In some diabetic patients excessively high HbA1c values with high-performance liquid chromatography (HPLC) led to the detection of Hb Graz. In addition to Hb Graz, other silent hemoglobin variants have been found in Austria. Here we review Hb Graz, Hb Sherwood Forest, and Hb Okayama detected while using HPLC for the measurement of HbA1c in diabetic patients.