This article analyses five types of international trade based on the competitive advantages afforded to under-developed countries by their environmental resources endowment. First of all, specialization of such countries in the production of highly polluting goods and services is studied, recalling the conventional specialization in the production and export of goods making intensive use of natural resources. The commercial exploitation of the recreational services of natural parks and the exploitation of biodiversity in pharmaceutical research is then referred to. The use for profit of some environmental services involving these resources which are in the nature of public goods and which would require some type of bilateral or multilateral international agreement is addressed. The access of these countries on an equal footing to a number of global and common resources is then considered, and finally some conclusions are presented. According to these conclusions, it is hard for trade relations between developing and developed countries, based on specialization in the use of the endowment of environmental and natural resources, to provide any solution to the problems of poverty and environmental degradation. However, more efficient, more imaginative and, in the final analysis, more equitable exploitation of these resources could make a much bigger contribution to the solution of these two serious problems. In this case, in order to attain economic and social efficiency it is necessary to receive the collaboration of the advanced countries, in view of the fact that environmental resources are in the nature of public goods.