During the past two years similar petroleum tax reforms have been proposed in Norway and Denmark. Both were based on results on neutral taxation derived by Boadway and Bruce (1984) and Fane (1987). In this paper the main features of the proposals are presented, and important problems of implementation are highlighted. Topics for further research are pointed out also. While the risk characteristics of tax deductions caused major disagreements between experts and oil companies, the after-tax cost of capital for risk free cash flows is a question less clearly resolved within the economics literature. Another topic for disagreement is value additivity, disputed by the companies.