Glycated hemoglobin A1c assay is performed using HPLC on cation exchange TSK SP 5 PW column. Separation is obtained in 10 minutes using graduated elution with sodium chloride and Bis-Tris buffer. Hb A1c is resolved from the other hemoglobins (F, A0 and S). Reproductibility of method is quite good and correlated with an immunologic method (DCA 2000).