The present research examines how Brazilian diplomacy has acted in cases involving conflicts over natural resources in South American countries, highlighting trends of regional integration and changes in the political landscape of the continent with the election of leftist leaders committed to change in their countries. Two specific cases are used to illustrate the international relations policy of Brazil to the region: a renegotiation of the price of Bolivian gas, and the terms of the bilateral treaty with Paraguay for the purchase of hydroelectric power. Finally, this paper concludes that a quest for regional leadership and energy integration across the continent forces Brazil to adopt a posture of cooperation with its neighbours in a conciliatory diplomacy of joint gains.