In recent years, technological developments have led to digital files being more easily distributed, for example through Napster (a file sharing service on the Internet). In order to manage and control the distribution of digital files, a new concept has been developed, called DRM (Digital Rights Management). The purpose is to set every single file with individual rights that are extremely hard to break, and consequently make people pay and use the files legally. The file will then be fully protected from intrusion and alteration until the set rights expire. The goal of this thesis is to look into and summarise DRM of today. We have concentrated on the mobile DRM market, and especially mobile phones. Especially the solutions/applications that already exist and their functionality and properties, but also requirements regarding security levels, compatibility etc. We have also added predictions of the near future, ours as well as others. Existing applications for DRM are well made but few are constructed for mobile phones. Mobile phones will however be a good and secure platform for DRM. At present there is no DRM application inserted in mobile phones in Europe. The third generation (3G) network will push the progress with the capability of broader bandwidth, with capacity of downloading more content to the phone. Since the mobile phone software is embedded and the mobile phones are within a trusted network, the security level of a DRM application in a mobile phone can be discussed. A lower level of security would make it easier for managing content but also open up the market for hackers that wish to trespass. With a lower level of security you always have to consider the consequences and often it creates more problems than it solves. We believe the DRM market and its value will increase exponentially over the next few years. The number of players on the mobile Internet DRM market will be less than on the Internet DRM market, due to the complexity of getting applications into the phone. The latter will consist of many more players, and remain fragmented, since it is an open market.