SUMMARYOver the last decade many research groups and commercial companies have been developing reengineering environments. However, many design decisions such as support for multiple models, incremental loading of information, tool integration, entity grouping, and their impacts on the underlying meta-model and resulting environment have remained implicit. Based on the experience accumulated while developing the Moose reengineering environment and on a survey of reengineering environments, we present a design space defined by a set of criteria that makes explicit the different options and especially their dependencies and trade-offs. Using this design space, developers of future environments should have a better understanding of the problems they face and the impact of design choices.