This paper discusses the recent work of the authors in developing Integrated CASE (ICASE) tools which support multiple development notations. We use a four-step methodology to develop these integrated tools. The conceptual data models of different notations are first developed, and then merged into an integrated conceptual data model. Dynamic mappings between different notations components are used to describe how related notation components are kept consistent under change. The conceptual data models and mappings are used to implement individual CASE tools for each notation. Separate tools are then integrated by linking their repositories via a shared repository based on the integrated conceptual data model. We discuss extensions to this work which will provide MetaCASE facilities for environment generation and evolution.