This book constitutes the refereed proceedings of the 5th International Symposium, Latin American Theoretical Informatics, LATIN 2002, held in Cancun, Mexico, in April 2002.The 44 revised full papers presented together with a tutorial and 7 abstracts of invited contributions were carefully reviewed and selected from a total of 104 submissions. The papers presented are devoted to a broad range of topics from theoretical computer science and mathematical foundations, with a certain focus on algorithmics and computations related to discrete structures.