A certified translation is a translation that comes with a statement from the translator attesting to his or her knowledge of the source (the language being translated) and the target (the language of the translation) languages. A certified translation is a standard requirement by many government agencies around the world. In the USA, for example, a certified translation is often required by the United States Citizenship and Immigration Services or the USCIS.
A certification of translation accuracy also know as affidavit of translation accuracy must follow any certified translation. Accuracy and completeness are the most important precepts of any certified translation. In countries other than the USA, certified translations are done by special translators who are not only certified but can also be sworn in by the government.