The invention concerns compositions and methods for preparing recombinant adenoviruses. The resulting adenoviruses can be used for transferring and/or expressing genes in cells, in vitro, ex vivo or in vivo, or also in functional genomics. More particularly, the invention concerns in particular efficient methods for producing adenovirus banks and the use of said banks in functional genomics. The invention also concerns plasmids used for constructing said adenoviruses.