This article examines the issues raised by the efforts of some states to tax the pension income of their former residents and of the proposed congressional legislation to forbid such taxation. While there may be sound policy reasons for forbidding state taxation of nonresident pension income, they have yet to emerge clearly from the rhetoric that has thus far dominated the debate over the pension tax issue. The goal of the article is to examine the questions raised by the controversy over state taxation of nonresident pensions in the hope that dispassionate analysis of the problem may contribute to a fair solution of it. It first addresses general principles regarding state taxation of personal income. Second, the article addresses state general principles of taxation of federally deferred income. Next, considerations and practical difficulties regarding state taxation of nonresident pension income are addressed. The article arrives at the conclusion that these difficulties may justify the proposed congressional restriction, even though states may react to such legislation by seeking to tax departing residents on their accrued pension income.