This article presents a general overview of the issues pertaining to whether the traditional source rules are still appropriate or whether new source rules are needed for the 21st century. The article advocates an origin-based interpretation of the term "source" and argues in favour of capital and labour-import neutrality and a source-based approach. The article first addresses the concept of source from a juridical perspective and identifies a multitude of meanings used in source rules in international tax law. Regarding economic policy, the article suggests that, given the globalization of economies, states should rethink the economic policy underlying their tax system. The article also considers some EU aspects (the case law of the European Court of Justice supports a source-based tax system but the directives in the field of direct taxation do not) and some treaty aspects (the residence-based OECD Model Tax Convention has flaws which offer opportunities for tax planning). Finally, the article outlines alternative origin-based source rules for some classes of income and deductions.