The implementation of the technology key learning area in the primary school sector during the last few years has resulted in issues being raised relating to teachers' knowledge of technology, and their propensities for incorporating it into an already packed curriculum. During the study reported in this paper, three teachers designed and implemented units of work around ideas which they drew from the national statement on technology, A Statement on Technology for Australian Schools (Curriculum Corporation, 1994). These teachers were faced with challenges to their various teaching professional knowledges and to their prior and developing understandings of the conceptual and procedural aspects of technology. A theoretical model for professional development is thus presented in the light of these teachers' experiences. The model highlights the need for professional developers to be aware of the impact that teachers' prior knowledge and beliefs about teaching and learning and about technology can have upon the meaning they make of the key learning area. The model also stresses that there is need for a combination of theoretical, practical and reflective experiences to be built into professional development programs on technology to provide teachers with the opportunities they may need to develop their understandings, while at the same time represent and promote technology as a process, as well as a product.