Stereoregular poly-amido-saccharides bearing α-glucopyranose branches (Mal-PASs) are synthesized by anionic ring-opening polymerization of a maltose-based β-lactam monomer followed by debenzylation. The polymerization affords high molecular weight polymers (up to 31500 g/mol) with narrow dispersities (Đ < 1.1). Deprotected Mal-PASs are highly soluble in water and adopt a left-handed helical conformation in solution. Turbidimetric assay shows that Mal-PASs are multivalent ligands to lectin Concanavalin A.