We compare measurement of total fast hemoglobin (HbA1) by "high-performance" liquid chromatography and by electrophoresis on agar gel. Blood samples were obtained from a diverse population (n = 222): offspring of two diabetic parents, diabetic patients with and without retinopathy, diabetic and non-diabetic pregnant women, patients in the coronary-care unit, and normal persons. Precision studies with a normal and an above-normal A1 sample resulted in overall CVs of 9.0% and 4.6% for the electrophoretic method and 4.4% and 2% for the chromatographic method. Linear regression analysis of values for total fast hemoglobin for the complete sample population and for each subgroup showed results of the electrophoretic method to be in excellent agreement with those by the chromatographic method. We conclude that the agar gel electrophoretic method offers a reproducible means for HbA1 determination that is comparable to the HPLC method in terms of accuracy and is highly suited for routine laboratory use.