This book constitutes the refereed proceedings of the 5th International Conference on Foundations of Software Science and Computation Structures, FOSSACS 2002, held in Grenoble, France, in April 2002.The 28 revised full papers presented together with an extended abstract of an invited paper were carefully reviewed and selected from a total of 67 submissions. Among the topics addressed are algebraic, categorical, logical, and geometric theories, models and methods which support the specification, synthesis, verification, analysis, and transformation of sequential, concurrent, distributed, and mobile programs and software systems.