This book constitutes the refereed proceedings of the 10th International Workshop on Abstract State Machines, ASM 2003, held in Taormina, Italy in March 2003. The 16 revised full papers presented together with 8 invited papers and 12 abstracts were carefully reviewed and selected for inclusion in the book. The papers reflect the state of the art of the abstract state machine method for the design and analysis of complex software/hardware systems. Besides theoretical results and methodological progress, application in various fields are studied as well.