Polymerase chain reaction (PCR) mediated DNA fingerprinting has resulted in the identification of a novelCampylobacter jejunigene, encoding a GTPase protein. The gene, consisting of 383 amino acids contained semi-conserved GTP-binding sites (designated G-1 to G-4), that are characteristic for members of the GTPase protein superfamily. Remarkably, this gene fromC. jejuniappears to encode a member of a novel family of GTP-binding proteins, containing two separate putative GTP-binding domains, each comprising a series of semi-conserved GTP-binding motifs. Spacing between these motifs is highly conserved. Based on this novel gene, a general PCR strategy for the identification ofC. jejuniC. coliC. lariandC. upsaliensiswas developed. PCR primers were deduced from GTP-binding motifs G-1 and G-3 of the first GTP-binding domain. These GTP-binding sites flank a variable region of precisely 117 bp in the fourCampylobacterspp. that allowed the development of species-specific probes. This PCR-hybridization assay offers a novel tool for rapid molecular detection and specific identification of the thermophilicCampylobacterspp.