Fluoroquinolones are a synthetic class of antibiotics, which all act by inhibition of DNA-gyrase abolishing its activity by interfering with the DNA rejoining reaction. Since gyrase is an essential enzyme in prokaryotes, but is not found in eukaryotes, bacteria are an ideal target for these antibiotics. Fluoroquinolones are mainly active against Gram-negative bacteria and have found wide application in both human and veterinary clinical practice. However, the use of fluoroquinolones in animals used for meat production and its use in aquaculture has also generated concern, as fluoroquinolones have contributed to an increasing bacterial resistance for these antibiotics in man, e.g. Staphylococcus aureus (MRSA, MRSE), Campylobacter jejuni and others. For this reason, effective screening methods for the presence of fluoroquinolones in animal products as well as food products are required. Community MRLs have been established for a number of fluoroquinolones, i.e. difloxacin, sarafloxacin, marbofloxacin, danofloxacin, oxolinic acid, and the sum of enrofloxacin/ciprofloxacin.