A routine detection assay of Campylobacter jejuni was developed with the polymerase chain reaction (PCR). A pair of oligonucleotide primers from the flaA of C. jejuni were used in detection by PCR. Although the primer pair specifically detected C. jejuni strains, they did not detect strains of C. coli, C. fetus, Salmonella spp. or Escherichia coli. In litter inoculated with C. jejuni, specific detection of C. jejuni was obtained by PCR with this primer pair.