The use of sustainability criteria in a binding legal context, in order to promote environmental sustainability, has so far not been thoroughly researched. Nor have the typical difficulties and challenges of including sustainability criteria in a legal framework been specified. Effective mechanisms for implementation and control of the fulfillment of sustainability criteria have neither been worked out. The main purpose of this thesis is to develop an approach, and with its help to investigate how sustainability criteria can be used as a tool in a legal context to promote sustainable products and sustainable production. Two theoretical models have been combined and applied in structuralizing and analyzing the collected empirical material. Sustainability criteria have been viewed as part of a larger structural unit incorporated in a legal framework, where all elements serve to provide efficient enforcement and fulfillment of these criteria. There has been special focus on the issue of control of the fulfillment of legislated sustainability criteria, and how this control might possibly be organized.