A simple high-performance liquid chromatographic method for the determination of 2-deoxy-D-glucose and D-glucose in rat serum is described; this method is based on a post-column fluorescence derivatization. The sugars are automatically converted into fluorescent derivatives by reaction with meso-1, 2-bis(4-methoxyphenyl)ethylenediamine in an alkaline medium after their separation on a strong anion exchanger column (TSK gel Sugar AXG). The detection limits (S/N=3) for 2-deoxy-D-glucose and D-glucose in rat serum are 0.52 and 0.56 nmol/ml, respectively.