A simple and rapid analytical method for the structural identification of sugar chains involving lectins and ultrafiltration was developed. In the procedure, a mixture of fluorogenic sugar chains is mixed with an unmodified lectin. Unbound sugar chains are removed by ultrafiltration. Qualitative differences between sugar chains from the sample and from the filtrate were determined by high performance liquid chromatography. The structures of different sugar chains could be determined from the specificity of the lectins used. Because the lectins used for the procedure were not modified, both the lectins used and sugar chains could be recovered. The method is simple and can be used for structural analysis of sugar chains.