This book constitutes the refereed proceedings of the 12th International Conference on Compiler Construction, CC 2003, held in Warsaw, Poland, in April 2003.

The 20 revised full regular papers and one tool demonstration paper presented together with two invited papers were carefully reviewed and selected from 83 submissions. The papers are organized in topical sections on register allocation, language constructs and their implementation, type analysis, Java, pot pourri, and optimization.