Abstract Recent structural studies demonstrated that the epitope recognized by a monoclonal antibody representative of the protective response against the type III Group B Streptococcus polysaccharide was comprised within two of the repeating units that constitute the full-length native structure. Here we took advantage of this discovery to design a novel vaccine based on multivalent presentation of the identified minimal epitope on a carrier protein. We show that highly glycosylated short oligosaccharide conjugates elicit functional immune responses comparable to the full-length native polysaccharide. The obtained results pave the way to the design of well-defined glycoconjugate vaccines based on short synthetic oligosaccharides.