Abstract: Systems and methods are provided for automatically delivering media files with advertisements over a network. A method and system is disclosed for automatically adding an advertisement to the beginning or the end of a media file, such as a podcast episode, when the media file is requested by a consumer. In another aspect, the media file may be automatically searched for an advertisement marker, such as a specific tone or data element in the media file, that acts as a submission point for the automatic insertion of an advertisement into the media file. Aspects of the present invention allow for automatic insertion of advertisements after the creation of the media file, potentially without any interaction between the creator and the advertiser. The systems can be implemented at a central server, at the media file source, at a consumer's media player or distributed throughout various computing devices.