This paper presents and discusses the possible theoretical bases of a comprehensive approach of robust eco-design to reduce the variations of the environmental impact of a product, compared to the baseline. The goal is to overcome the main limitations of contributions to the state of the art, i.e. the lack of a single approach to treat all possible causes, practical application and rigor in discussing the issues of environmental sustainability. The proposal is the intersection between eco-assessment, design theories and robust design. The eco-assessment provides the basis for an initial formulation of the environmental problems to be faced, which are correlated to the variation of the impacts. The design theories allow, through their ontology, to reformulate environmental problems in a more appropriate way to be addressed by the designer and at the same time provide, together with the robust design methods, suggestions to search the solutions. The analysis presented and the application proposal help to show the complexity and heterogeneity of the topic and reinforce the idea of introducing a systematic methodology to select the most appropriate method and favour its targeted use.