This book constitutes the refereed proceedings of the 6th International Workshop on Randomization and Approximation Techniques in Computer Science, RANDOM 2002, held in Cambridge, MA, USA in September 2002.The 21 revised full papers presented were carefully reviewed and selected from 48 submissions. Among the topics addressed are coding, geometric computations, graph colorings, random hypergraphs, graph computations, lattice computations, proof systems, probabilistic algorithms, derandomization, constraint satisfaction, and web graphs analysis.