Government choice of which taxation regime to adopt on oil determines how the revenue generated by the activity of exploring and producing this oil is shared between the State and private investors. From the point of view of the State, it is extremely important to choose a regime that does not detract private investors and that is also capable of generating enough revenue to bolster the country´s economy and promote the well-being of its population. The present work studies the main taxation regimes on oil, identifying how the income generated by this product is distributed between government and private investors. It also calculates the level of risk for agents in both regimes analysed. The aim is to verify if these regimes comply with the main requirements necessary for a regime to be considered efficient − simplicity and neutrality – and if there is a relation between the kind of regime and the variables mentioned above.The main taxation regimes in the world are concession and sharing. The regimes adopted by Australia, Norway, Brazil and Indonesia were studied. The first three countries adopt the concession regime, while the latter adopts the sharing one. The Australian regime – in which government remuneration was obtained by two taxes − was the simplest of all analysed regimes, while that of Indonesia – in which government remuneration was obtained by five taxes − was the most complex. The Brazilian regime is considered to be simple: government revenue is obtained by means of three taxes. The distribution of the revenue generated by oil exploration and production is more balanced in Australia, where private investors receive around 16.6% and the government around 88.4%. In Brazil private investors gain 9.16% and the government 90.84%.The regimes in Norway and Indonesia penalize the private investor; the field presents a positive net current value prior to taxes and negative after taxes. Brazil and Australia displayed positive net current value prior to and after taxes levied. The findings suggest that there is no relation between the kind of regime and the following variables: equity in income distribution, neutrality, and investor and government risk. Countries that adopt the same regime – concession – presented different characteristics. The regime adopted by Norway penalized the private investor, while that of Australia distributed revenues more equitably. As regards risk, the regime with greatest risks for private investors was the Indonesian, while the one with least risks was the Australian. Brazil ranked third in both categories. Thus, a regime cannot be considered more efficient than another. The main issue is how taxes are levied within each regime. Given that the Brazilian oil reserve has reached unprecedented levels, discussion should focus on how oil will be taxed in the present regime (concession), rather than on the taxation regime adopted.