Large scale immigration to the United States and a sluggish national economy have brought to the forefront of the current immigration policy debate, the question of whether immigrants fully pay—in the form of taxes—for the public services they use. Recent estimates of the costs of immigration differ so widely that they have confused rather than enlightened that debate. This paper argues that a uniform accounting framework must be agreed to if future studies are to provide credible and reliable estimates of costs and benefits upon which immigration policy can be formulated. The key conceptual, factual, and accounting issues that are to be addressed for the development of such a framework are outlined.