A gas chromatographic method for the determination of neutral and amino sugars in glycoproteins [human semen] was developed by using trifluoroacetyl [TFA] derivatives of sugar alcohols and by selecting trifluoroacetic acid as acid catalyst for hydrolysis. The method is as follows: the hydrolytic condition, 2.5 N TFA, 100.degree. C, 7 h was common to obtain excellent recovery of neutral and amino sugars in many glycoproteins. In the case of having enough sample, it was recommendable to select 4 and 7 h for hydrolysis of neutral sugars and 7 and 10 h for amino sugars. In sample preparation for gas chromatography, sugars were reduced with sodium borohydride to corresponding sugar alcohols and trifluoroacetylated with trifluoroacetic anhydride in ethyl acetate. This method was further improved for micro-analysis of sugars in glycoproteins, taking full advantage of the sensitivity of an electron capture detector (ECD) to trifluoroacetyl derivatives. It was suggested to be able to analyze constituent neutral and amino sugars in microgram amounts of glycoproteins.