The deliberate and accidental relocation of birds and mammals around the globe has been and continues to be integral to patterns of human population spread, settlement and economic development. The outcomes of these relocations have been and may be irreversible, with long-term positive and negative implications for ecological, economic and recreational values. Therefore, for each such relocation there are benefits and/or costs which may not always be predictable but which can be realistically assessed and evaluated. A critical point may have been reached in society's recognition of the value of global biodiversity and its wish to mitigate threats to this. Therefore the OECD invited 16 leading scientists in the area of wildlife ecology to review the existing knowledge about vertebrate introductions, and to formulate recommendations for handling such introductions on a sound scientific basis in the future. These recommendations include a proposal to regulate all introductions of exotic vertebrates, to consult neighbouring countries and the public about such introductions, to adopt a combined white-list/black-list approach, and to establish national advisory committees for recommending actions in these questions.