This book constitutes the refereed proceedings of the 10th International Symposium on String Processing and Information Retrieval, SPIRE 2003, held in Manaus, Brazil, in October 2003.The 21 revised full papers and 6 revised short papers presented together with 2 invited papers were carefully reviewed and selected from 54 submissions. The papers are organized in topical sections on Web algorithms, bit-parallel algorithms, compression, categorization and ranking, music retrieval, multilingual information retrieval, subsequences and distributed algorithms, and algorithms on strings and trees.