Campylobacter has emerged as the leading cause of bacterial foodborne infections in developed countries over recent years. Epidemiological studies reported a constant increase of campylobacteriosis cases representing a significant economic burden worldwide. As an obligate microaerobic bacterium, Campylobacter puzzled scientists as to how it could survive from the farm to retail outlets. In order to propose effective control strategies, a better understanding of its adaptation, virulence, and survival in food products and the food environment is critical. Considering the enigmatic behavior and the idiosyncrasy of Campylobacter jejuni, many of its biological functions could not be inferred only from bacterial genomic comparisons. Consequently structural, functional and expression proteomics analyses performed on Campylobacter have been invaluable in unraveling the biological pathways and responses of Campylobacter. This chapter gives the main discoveries using proteomics tools since 2000 on Campylobacter sp