Flagella are essential for motility and have been implicated to be one of the pathogenic determinants. The flagellum of Campylobacter jejuni is a polymeric structure of a 62-kd protein. Using a high-affinity flagellin antibody to screen a lambda gt11 phage genomic expression library of C. jejuni strain TGH9011 (Serotype LIO36), a recombinant phage clone lambda gt11RK that expresses the C. jejuni flagellin protein was isolated. The recombinant lambda gt11RK produced a 56-kd protein upon induction with isopropylthiogalactoside, which reacted specifically with anti-flagellin antibody. The flagellin gene was sequenced, and comparative analysis of the nucleotide and amino acid sequence identified a region of the flagellin that shows hypervariability among different Campylobacter species and strains.