The sustainable design of complex building types such as laboratories and hospitals can be particularly challenging, given their inherent complexity of systems, health and safety requirements, long-term flexibility and adaptability needs, energy use intensity, and environmental impacts. Tools such as design guides, energy benchmarking, and LEED rating systems are especially helpful to support sustainable design in such buildings. Furthermore, designers need guidance on how to effectively and appropriately use each tool within the context of an integrated design process involving multiple actors with various objectives. Toward this end, the Laboratories for the 21st Century (Labs21) program has developed an interlinked set of tools - the Labs21 Toolkit - to support an integrated design process for sustainable laboratories. Labs21 is a voluntary partnership program sponsored by the U.S. Environmental Protection Agency (EPA) and U.S. Department of Energy (DOE) to improve the environment al performance of U.S. laboratories. In this paper, we present the Labs21 Toolkit, and illustrate how these tools can be used to support sustainable design within an integrated design process. The tool kit includes core information tools, as well as process-related tools, as indicated below: Core information tools: -A Design Guide, which is a compendium of publications on energy efficiency in laboratories -Case Studies that showcase high-performance design features and applications. -Best Practice Guides that highlight industry-leading sustainable design strategies. -A web-based Benchmarking Tool to benchmark laboratory energy performance.Process tools: -A Design Intent Tool, which can be used to used to plan, document, and verify that a facility's design intent is being met at each stage of the design process. The Environmental Performance Criteria (EPC), a rating system specifically designed for laboratory facilities that builds on the LEED(TM) system. -A web-based Process Manual, that provides a 'portal' to the tools and a step-by-step process for using these tools during each stage of the design process.