The top managers of a biotechnology startup firm agreed to participate in a system dynamics modelling project to help them think about the firm's growth strategy. The paper describes how the model was created and used in order to stimulate debate and discussion about growth management.There were several novel features about the process used for capturing management team knowledge in the model, and for representing unique structural features of biotechnology manufacturing and marketing. The paper highlights these novel aspects of conceptualisation. A heavy emphasis was placed on mapping the operating structure of the factory and distribution channels. In addition, much time and effort was spent on choosing model concepts and vocabulary suited to the business and to thinking carefully about units of measure and dimensions. Qualitative modelling methods (structural diagrams, long variable names and friendly documented algebra) were used extensively to capture the management team's description of the business.The size of the model (and partial models) was kept deliberately small to ensure the involvement of the management team. Simulation scenarios were designed to stimulate debate about strategic issues such as capacity allocation, capacity expansion, customer recruitment, customer retention and market growth. The paper describes how the management team was 'drawn-in' to using the computer to design and debate their own strategic scenarios. The paper concludes with comments on the impact of the project.