The objective of this study was to evaluate PCR and fluorescent in situ hybridization (FISH) techniques for detecting Arcobacter in river water and wastewater samples. Both 16S and 23S rRNA sequence data were used to design specific primers and oligonucleotide probes for PCR and FISH analyses respectively. In order to assess the suitability of the methods, the assays wereperformed on naturally and artificially contaminated samples, and compared with the isolation of cells on selective media. The detection range of PCR and FISH assays varied between 10 cells (after enrichment) to 103 cells per ml (without enrichment). Results showed that both rRNA-based techniques have the potential to be used as quick and sensitive methods for detection of Arcobacter in environmental samples. Includes 18 references.