In this essay Mason demonstrates that Halliday's systemic grammar might make a more productive contribution to translation studies if a grammatical feature is considered in connection with a particular social factor, such as the institutional sites of translating. Taking translations of documents from the European Union and UNESCO, Mason scrutinizes shifts in transitivity, the linguistic representation of reality through such categories as agent, action and circumstances. Since the documents he analyses involve extremely controversial problems like Mad Cow Disease, the examination of transitivity actually discloses the ideologies upheld by the translations. The essay reveals that the linguistic analysis of institutional translations can expose ideological determinations towards which the analyst necessarily, even if unintentionally, takes a stand. To expose an ideology in translation designed to function as impartial communication is not to accept that ideology as true or right, but to treat it with critical detachment.