In this paper we propose a model to analyse the motivation of academic entrepreneurs that comprises six dimensions: personal, relating to the entrepreneurial opportunity, to scientific knowledge, to the availability of resources, to the incubator organization, and to the social environment. The model is tested based on information from a survey administered to 152 Spanish academic entrepreneurs. Our results show that entrepreneurial opportunity is not part of the entrepreneurial motivation, but is of
the utmost importance to academic entrepreneurs. Also, we find the scientific knowledge is the main driver of entrepreneurial activity in the academia.