Summary A new technique for demonstration of lectin-binding sites is proposed. At the 1st step of the method, the lectin binds the respective monosaccharide constituent of the glycoconjugate and at the 2nd step, the blood-group substance A-ferritin conjugate is used as a marker. The following lectins were tested: wheat germ agglutinin, soybean agglutinin, mistletoe lectin I, and concanavalin A. Human red blood cells were used as material. By means of control experiments, the specificity of the proposed technique was proved.