This paper focuses on companies within the cleantech industry (clean technology and its derivation “cleantech”) that have started up and produced clean techniques to the industrial world. The main purpose of this study is to contribute a better understanding of cleantech entrepreneurs’ motivations and influences to start up a cleantech company. This understanding, in turn, will provide regulatory agencies and society the key factors to stimulate cleantech entrepreneurial activity which take the environment and social problems into consideration. Thus, this study attempt to answer the following question: Why do entrepreneurs choose to run a cleantech company? In order to fulfill the main purpose of this project, a qualitative study was conducted. The qualitative study was performed as an unstructured interview of twelve founders of cleantech companies.  The cleantech companies were still in the in the start –up stage and some are at an even earlier stage. The companies were selected with the assist of Swentec’s mapping of cleantech companies in Sweden and ETAPs (Environmental Technologies Action Plan). In the theory chapter, this study contributes with a new framework of motives and goals for ecopreneurship. This new framework originates from the studies on the driving forces of ecopreneurship (Schaltegger (2002), Linnanen (2002), Valley & Taylor (2002) and Pastakia (2002).  The new framework recognizes four new types of ecopreneurs: eco-idealists, eco-innovators, ad-hoc enviropreneurs and environment opportunist. This typology is used to position and analyze cleantech entrepreneurs who participated in this study. In the empirical chapter, the findings revealed that the cleantech entrepreneurs’ motivations lie primarily in the opportunity to convert their innovation of techniques into concrete business and succeed in the private sector. Due to the fact that the great majority of entrepreneurs are academic researchers with a doctoral degree in engineering, their personal motives can be characterized as the pursuit of a “need for achievement”, “independence” and “extensive experience” in the field of cleantech development.  Furthermore, the cleantech entrepreneurs were thoroughly engaged in social and environmental problems. They pursue sustainability because they believe that their work contributes to create sustainable values in society. As a result, cleantech entrepreneurs are ecopreneurs. This study also showed that these values require influencing factors such as law and regulations, customers who demand clean technology in their manufacture of products, services and overall processes.  However, the cleantech companies argued that this influences especially regulations not provide enough incentives for cleantech development in order to address the environmental problem successfully. An implication of these findings is that government’s support should not be an obstacle but ensuring a sustainable society.