The EC Directive (91/492/EEC) on Shellfish Hygiene requires all Member States to classify their shellfish harvesting areas into one of three categories according to the degree of faecal indicator bacteria present in samples of shellfish flesh. Historically, a limited amount of bacteriological data for England and Wales has been collected by Local and Port Health Authorities, the National Rivers Authority, the Ministry of Agriculture, Fisheries & Food and other smaller organisations involves in survey work. However, in order to provide definitive classifications before 1 January 1993, it is necessary to implement on-going monthly sampling programmes at fixed points within each shellfishery. Consequently standardised sample collection protocols and laboratory methodologies have been developed and these are discussed.