The detection of Campylobacter jejuni by sensitising the surface of an optical fibre long period grating (LPG) with a covalently attached rabbit polyclonal antibody is explored. Previous reports have exploited the use bacteriophages as recognition elements for bacterial detection, while antibodies have been used to detect biochemical interactions. However, to date the use of antibodies for bacterial detection has not been explored widely. It is shown that it is possible to detect bacteria using antibody concentrations as low as 10 μg/ml.