This paper primarily deals with the peculiarities of determining binding substantitive law and not with the question of international authority. The first part deals with the practical need for collision law regulation with particular attention to the peculiarities of Internet transactions and trade. The second part gives a review of normative collision law consumer protection firstly at national law level and then at the international level. In the last part of the paper, the authors discuss the Croatian legal system, give a brief review of substantitive law solutions and discuss the shortcomings of existing collision law rules and the prospective development thereof. The authors especially refer to EU (European Union) trends and the successful application of Community patrimony (acquis communitaire) in Croatian collision law.