The government's tobacco control policies are often multifaceted and large-scale in nature. The process and outcome evaluation of such programs generally requires a significant investment in time, money, and effort. A critical but often neglected step prior to conducting a successful evaluation is the evaluability assessment. This tool is a method for examining a given program to determine whether it meets the criteria for a meaningful evaluation. Even when it fails to do so, it still contributes to the improvement of the program. This article describes the principles of the evaluability assessment and provides an example of its application. It concludes by presenting some lessons learned from the evaluation of Quebec's Quit Smoking Centres.