This paper addresses tariff revenue concerns that some countries have been expressing in the context of the current multilateral trade negotiations under the Doha Development Agenda. This paper: discusses methodological issues associated with estimating revenue impacts; provides impact estimates for a sample of developing countries; links the differences in impacts to cross-country differences in existing tariff regimes as well as properties of formulas for tariff cuts; and, discusses efficient tax replacement policies and past experiences. Additionally, the paper presents results of a simulation of the welfare effects of reducing tariffs and simultaneously replacing lost tariff revenues with revenues from consumption tax. It concludes with some policy implications.