Asylum policy decisions by the states are largely founded on informal cooperation between the asylum authorities of different european countries. Based on interviews and observations the author identifies conditions for informal transnational cooperation on asylum policy to take place. It is argued that cooperation most likely occurs when countries (or rather their national asylum authorities) share problems and solutions, have a similar history regarding the creation of asylum authorities and have a similar language and administrative structures. Informal governance proceeds according to a number of rules. As soon as these rules are (or can) no longer be adhered to, they have to be formalized. Three case studies illustrate the theoretical assumptions and show that european asylum governance is progressing towards more formal regulations.