Abstract: Disclosed herein are immunogenic polysaccharide-H. influenzae adhesin protein conjugates, a purified H. influenzae adhesin protein and related proteins and polypeptides, DNA useful for producing the proteins, synthetic polyribosylribotol phosphate (PRP) oligosaccharides and intermediates useful for their synthesis, and methods of making and using these materials. The conjugates comprise a PRP fragment, preferably a synthetic oligosaccharide, coupled to an H. influenzae adhesin protein. The invention further comprises purified H. influenzae adhesin proteins and novel PRP oligosaccharides. The invention also comprises methods of producing these materials and using them in a vaccine to protect humans and other mammals against H. influenzae infection.