This volume contains the proceedings of EMSOFT 2001, the First International Workshop on Embedded Software. The workshop was organized October 8-10, 2001, at Tahoe City, California. The steering committee of the workshop has the following members: G' erard Berry (Esterel Technologies, France) Paul Hudak (Yale University, USA) Hermann Kopetz(Technical University of Vienna, Austria) Edward Lee (University of California, Berkeley, USA) Ragunathan Rajkumar (Carnegie Mellon University, USA) Alberto Sangiovanni-Vincentelli (University of California, Berkeley, USA) Douglas Schmidt (Defense Advanced Research Projects Agency, USA) Joseph Sifakis (Verimag Grenoble, France) The workshop was sponsored jointly by the DARPA Information Technology O?ce within the MobIES (Model-based Integration of Embedded Systems) p- gram (Dr. Janos Sztipanovits), and by the National Science Foundation (Dr. Helen Gill). The workshop URL is www. emsoft. org. Embedded software is software that interacts with physical processes. As - bedded systems increasingly permeate our daily lives on all levels, from micr- copic devices to international networks, the cost-e?cient development of reliable embedded software is one of the grand challenges in computer science today. The purpose of the workshop is to bring together researchers in all areas of computer science that are traditionally distinct but relevant to embedded software devel- ment, and to incubate a research community in this way.