African oil-producing countries are facing numerous contradictory pressures on their oil tax policies: a fall in tax revenues due to tax competition between these countries (a competition that is organized by Northern countries in order to maximize non-OPEC production); and an increase in capital and production costs in deep off-shore operations due to the depletion of existing reserves, thus reducing profitability as well as tax revenues. Simultaneously, competition between international oil companies and an increase in prices produce positive effects on tax revenues. Any improvement in revenue transparency, to which the international community wishes to contribute, would need to be based on improved models of oil revenues and policies for each of the producing countries.