Chapter 3 analyses how evidence has become a central element of the FCTC regime (2005–present). Section 3.1 captures the most important developments since the conclusion of the FCTC in 2003. Section 3.2 provides the theoretical framework of the chapter, focusing on the concept of path dependence in international organisations. Section 3.3 proceeds by showing that the development of the guidelines by the FCTC Conference of the Parties (COP) has been in effect a continuation of the strategy on evidence. Section 3.4 in turn highlights the second facet of the FCTC as an evidence-based regime, that is how the FCTC has mobilised new evidence at the national level. Sections 3.5 and 3.6 reflect on the consequences that the evidence-based approach has had on the outlook of the FCTC regime. Section 3.5 uses in-depth qualitative analysis to demonstrate that the evidence-based approach has reinforced the importance of the expertise of civil society organisations. Finally, Section 3.6 illustrates how the evidence-based approach has started to show its shortcomings in the work of the FCTC COP – particularly in the approach to new products like e-cigarettes (or ENDS) and in the (lack of) development of strategies to foster the implementation of tobacco control measures.