A simple spectrophotometric method for the dectermination of D-glucosaminate with bacterial D-glaucosaminate dehydratase (EC 4.2.1.26) has been developed. The method is based on the enzymatic dehydration of D-gluco-saminatie and the spectrophotomeric determination of the product, 2-keto-3-deoxy-D-gluconate, as its semicarbazone. A linear relationship was established between the absorbance at 250 nm of semicarbasone and the amount of D-gluco-saminate (0.05 - 1.0 μmol). The method was applicable to the determination of D-Glucosaminate in bacterial crude extracts.