This article examines the issues and the problems confronted by those conducting comparative research of charity-state relations in England, Canada and the United States. It also provides an explanation of why the interaction between charities and the state is important for political science: in part this is because in all three countries charities have become increasingly dependent on government for their income. In section I, the article examines the relationship between the concepts of a third sector, voluntary sector, non-profit sector and charity and concludes that the last might be the most appropriate to employ in comparative analysis. In section 2, the authors argue that in both England and Canada the state is formally responsible for the formation of certain kinds of charities; they also argue that in the United States a stricter separation between state and charity exists but that, in practice, the boundaries between charities and the state and the market are not clear ones.