Although transfer pricing rules only apply to transactions between associated enterprises the notion of "associated enterprises" is not much commented on by the OECD. Reference is mainly made to Article 9 of the OECD Model, but unfortunately this reference is not very precise. Countries have used their leeway for defining independently when companies are associated in such a way that application of transfer pricing rules is permitted. The goal of our comparative survey is to collect information about the definition of associated enterprises in the most important jurisdictions. We do not deal with transactions between head office and permanent establishment for two reasons: first of all the scope of the analysis would become to big for publication of many country reports in this journal, and secondly the issue has already, although in a slightly different context, been dealt with by this journal in 1996. The contributions contain a concise discussion of the concept of associated enterprises as used in the domestic legislation of your country, administrative guidelines, and case law (if any). To make the analysis more concrete a couple of more or less standard situations have been added. The impact of tax treaties on the definition of associated enterprises has been discussed as well.