[en] This study compared the impact of taxation on the economic viability and competitive position of uranium mining in Canada and Australia. The evaluation is based on four types of uranium deposit and four hypothetical project models. The deposits are assumed to have been discovered and delineated, and are awaiting a mine development decision. The models, initially appraised on a before-tax basis, are then subjected to taxation in each of six jurisdictions. Several taxation criteria are assessed in each case, including after-tax measures of investment incentive, discounted tax revenues, effective tax rates, intergovernmental tax shares, and comparative tax levels. The impact of taxation is shown to be both high and variable. The taxation systems in Saskatchewan and Australia's Northern Territory generate the most government revenue and provide the lowest incentive for investment. Canada's Northwest Territories and Ontario provide the best investment incentive and collect the least amount of taxes. South Australia and Western Australia tend to be positioned between these extremes. The study demonstrates that only the very best uranium mining projects have a chance of being developed under current market conditions, and even these can be rendered uneconomic by excessive taxation regimes. It follows that exceptionally good quality targets will have to be identified to provide the economic justification for uranium exploration. These realities will likely restrict uranium exploration and development activities for some time, not an unexpected response to a market situation where low prices have been caused largely by excess supply. (L.L.)