Method for transferring large supplier catalogs in a data transmission system including the Internet network, a marketplace site able to be addressed through the Internet network, a first plurality of customers connected to the Internet network and a second plurality of suppliers connected to the Internet network, each supplier having a catalog file of available goods to be supplied to any customer. The method includes the steps requesting by one supplier the transfer of its catalog file to the marketplace site through a B2B gateway by using a catalog control protocol, transferring the catalog file to the marketplace site through a catalog gateway by using a catalog transfer protocol, aggregating the catalog file received from the supplier to a general catalog, and publishing the updated general catalog onto a storefront web site so that any one of the customers can view the goods of the supplier.