Regulation theory offers a cogent analytical framework to explain the contemporary environmental challenge, capitalism's responses to environmental issues and the challenge of sustainable development to accumulation. The paper outlines the insights provided by this analytical framework and seeks to develop a regulationist approach to the ecological by building on two contributions directed at overcoming the past regulationist 'environment-deficit-syndrome'. It is contended that the economic-environment relation is not a social relation peculiar to capitalism but is given definition and form by the mode of regulation which secures accumulation. A method for empirical investigation of the economic-environment relation is proposed and it is concluded that the prospects for sustainable development are constrained to that which do not challenge accumulation. Thus, regulationist analysis can provide a more realistic picture of capitalism's challenges to be overcome to achieve the more equitable solutions sought by Green Economics to climate change, poverty and biodiversity.