This study examines decision making in large and small firms undertaking biotechnology innovation and identifies factors influencing innovation. It also considers aspects of environments external to firms, but relevant to the process of innovation. The study suggests that innovation is best understood as process of change both within the firm and in the external environment. Factors internal to firms influencing key decisions included economic and political evaluations, company culture, organization, and in large firms, previous areas of corporate activity. A scarcity of appropriate knowledge relating to technical and non-technical aspects of innovation acted as severe restraints to Dedicated Biotechnology Firms (DBFs). Factors external to firms shaping decisions about the technology included changes in the socio-economic and political environment, risk regulation and patenting. Lack of funding and difficulties associated with venture capital constituted additional hurdles for DBFs. The findings of the study highlight a series of erroneous assumptions built into the linear model of innovation. The cumulative nature of innovation and the importance of 'learning by doing' constitute elements of the critique of the linear model. For related reasons, some Post Fordist theories of current change in advanced industrialized countries, particularly those which advocate flexible specialization as a new model for industrial growth also prove problematic.