This thesis intends to analyze and clarify the legal position regarding abuse of a dominant position and particularly tying practices. The practice is central within European competition law and has been highly discussed in literature recently. In Article 102 TFEU it is explicitly stated that supplementary obligations which have no connection with the subject of such contracts, shall be considered as a way of abusing a position of strength. Although the method is often reasonable and very common within many business areas, it might be pursued as a tactic of excluding competition. The General Court’s decision in Microsoft led to some confusion as regards to the European approach towards tying practices. Prior to that judgment, the EU Courts appeared quite negative to the practice and seemed determined that the practice was in fact anticompetitive. For an example, in Hilti the Court found it sufficient that the company had deprived its costumers of a choice. The effects on competition were not analyzed in great detail and in most cases the EU Courts fined the undertaking involved in such business methods. However, in Microsoft the General Court took a new approach and focused on the actual effects that followed from the practice. Many argues that European competition law has moved from a per se approach to a rule of reason approach. In my opinion however, it seems relatively unclear whether or not this new approach shall apply to all versions of tying or if it was applied due to the certain circumstances involved in Microsoft. The tying practice involved a form of technical tying, i.e. an integration of two distinctive products. Cases prior to Microsoft mostly concerned a form of contractual tying and were treated very differently by the EU Courts. My opinion on the matter is therefore that it is not possible to declare a clear legal position regarding the practice of tying. There is a need for new judgments and official guidelines since the current situation deprives companies of legal security as concerns the practice of tying within European competition law.