The synthetic-peptide strategy was used to generate antibodies raised against calcium-dependent lectins of vertebrates. We demonstrate that a synthetic peptide predicted from the amino acid sequence of the carbohydrate recognition domain can induce blocking antibodies which would react with, or in close vicinity of, the binding site of the parent molecule. As the preselected sequence was chosen in a consensus sequence region, we also present preliminary investigations of the use of specific antisera as a common biological probe against calcium dependent lectins. The availability of monospecific polyclonal sera opens new possibilities in biochemical and structural studies as well as immunodection of calcium dependent lectins.