Estimation of the level of risk of faecal contamination of shellfish harvesting areas is undertaken by monitoring faecal indicator bacteria in seawater samples under the United States programme and shellfish flesh samples under the European Union (EU) programme. Determining the relationship between the two approaches is important for assessing the relative level of public health protection and regulating international trade. The relationship was investigated using both statistical modelling and simple compliance assessment on large international data sets of paired seawater and shellfish samples. The two approaches yielded the same conclusions: EU class A is more stringent than the US Approved category for all species; the US Restrictive standard is more restrictive than EU class B for some bivalve species. Therefore, the classifications under the two programmes are not exactly equivalent.