This paper presents the theoretical development of a model that uses the sender’s determination of the characteristics of the message to be transmitted as the basis of communication media choice, rather than the attributes of a particular technology. Using this viewpoint, a model is developed that illuminates the process of individual media choice, taking into account the technology available to, and currently used by, the sender. In addition, the effects of recipient’s characteristics and organizational norms and rules are shown. This model presents the key determinants of media choice and so enables the understanding of not only single medium choices; but also the use of multiple media in the workplace, how technology choices can be made for messages sent one-to-one, and to small and large groups. Testable propositions and everyday examples illustrate the model. Finally the implications of the model for research and practice are outlined.