This paper provides an overview of the process by which potential translators and interpreters demonstrate minimum standards of performance to warrant official or professional recognition of their ability to translate or interpret and to practise professionally-commonly known as "certification." Certification can be awarded by governmental or professional authorities on the basis of testing, completed training, presentation of previous relevant experience, and/or recommendations from practising professionals. Certification can be awarded by a single authority for all types of translation and interpreting, or by authorities that specialise in a particular mode or type of inter-lingual transfer. This paper compares certification procedures in 21 countries to present a cross-national perspective of how (and if) certification is awarded and which features and requirements are contained in it. The comparison reveals that the pragmatic, needs-based and socially focussed policies of translation and interpreting services in some New World countries such as Australia, Canada, and the US mean that a demonstration of ability level is performed in single tests. Successful completion of a test is the usual minimum requirement for certification, which itself may be specified according to general or specialised ability, or mode and context of inter-lingual transfer (e.g., "healthcare interpreter certification," "telephone interpreter certification"). In other, typically European and East Asian, countries a demonstration of minimum standards is provided through lengthy training, commonly as part of a university post-graduate degree where translation and interpreting performance is principally required for high-level political, business or literary interaction. In such countries, "certification" may be a term reserved for a restricted type of performance, e.g., court interpreting. Parallels are drawn between the procedures and conventions employed in various countries and how common elements may form a basis for greater cross-national equivalence and comparability. [ABSTRACT FROM AUTHOR]