In this paper, we describe how Motorola has deployed model-driven engineering in product development, in particular for the development of highly reliable telecommunications systems, and outline the benefits obtained. Model-driven engineering has dramatically increased both the quality and the reliability of software developed in our organization, as well as the productivity of our software engineers. Our experience demonstrates that model-driven engineering significantly improves the development process for telecommunications systems. We discuss the elements we found most important for deployment of model-driven engineering in a large product development organization: An appropriate modeling language, a powerful domain-specific code generator, and a deployment support team.