A previously described high pressure liquid chromatography system for the determination of glycosylated hemoglobin concentrations has been automated and simplified. With this methodology it is possible to perform up to 60 analyses per day for hemoglobin A1a+b% and hemoglobin A1c%. Where an estimate of the total fast hemoglobin alone is required, then a considerably greater number of analyses can be performed. The individual values are calculated directly with an electronic integrator. The mean coefficient of variation of the duplicate determinations of 48 samples was 0.63 +/- 0.83% (mean +/- SD). Aliquots of pooled hemolysates have been maintained in liquid nitrogen at -90 degrees C and run at the beginning and end of each daily analytical run over an 18-mo period. Both the inter- and intra-run coefficients of variation of these values have remained consistently less than 3%. Therefore, the methodology offers a reliable and accurate method of containing glycosylated hemoglobin values for clinical use.