This thesis is an attempt to improve the understanding of the process of adoption and diffusion of environmental innovations. The thesis is based on two research projects. One project deals with the diffusion of environmental innovations and why they are less successful on the market than other innovations. The other project is about the adoption of environmental innovations by Small and Medium Sized Enterprises (SMEs) and how to facilitate the adoption process.There are at least two good reasons why we should support the adoption and diffusion of eco- innovations. One argument from an environmental point of view is that successfully managing the environment is the greatest challenge facing us in the future and the global scenarios for the next decades are not encouraging. Another argument, from an economic point of view, for the need of eco-innovations is that the eco-industry is one of the most growing industries in the world and is likely to be worth around $600 billion worldwide by 2010.However, there are some indications that environmental innovations have a difficult time in gaining success in the marketplace and in spreading among potential customers, possibly more difficulty than some other kinds of innovations have.The overall objective of this thesis is to generate knowledge regarding the adoption and diffusion of environmental innovations. One purpose is to add to our understanding of environmental innovations and to their similarities and differences to “other” innovations. Another purpose is to understand and describe how networks can be used to facilitate the adoption of environmental innovations. The main research questions that I try to answer are:1) How can environmental innovations be classified? 2) Are environmental innovations less successful on the market than other innovations? 3) What are the main reasons for the differences in market success between environmental innovations and other innovations? 4) How could networks be used as a development method to facilitate the adoption of environmental innovations by SMEs?Several different methodological approaches have been used to develop a broader picture of different types of innovations and their development, adoption and diffusion. Two different approaches were used during the first project, dealing with the diffusion and market success of environmental innovations. The first one is mainly based on using questionnaires. The other approach is qualitative and based on case studies. Through a series of case studies of innovators and innovations we tried to achieve a better picture of the actual phenomena.The second project is about the adoption of an organizational environmental innovation by SMEs using a network. Since the goal of this project has been not only to observe the phenomena of the implementation of environmental innovation by SMEs using a network, but also to contribute to the development process, an action-oriented research approach was used in this project.Three main conclusions can be drawn on the basis of this thesis. Firstly, the new innovation classification system developed in this thesis improves the possibilities for distinguishing between innovations that are similar but not identical. A very large proportion of the analyzed eco-innovations are often classified as product redesign innovations. With the help of the new classification system it is possible to discern different types among those classified as product re-Vdesign innovations. Some are rather simple and accordingly classified as product care innovations, while others are classified as minor or major product improvements or even functional innovations. Secondly, our empirical studies results show that the environmental innovations are less successful on the market than “other” innovations. The empirical studies also show that there are mainly three factors which are especially important to consider in the improvement of environmental innovations’ marketing success. These three are: “Realism while evaluating one’s own innovation”, “Access to capital” and “Utilization of network”.Thirdly, to adopt an environmental innovation is not an easy task for small organizations, such as SMEs. But to be a part of and use a network is a possible way to facilitate the adoption process.