The articles in this collection were presented at the 11th International Conference of the Chilean Computer Science Society held in Satiago, Chile on October 15 - 18, 1991. A record number of 85 submissions were received this year in response to the call for papers. They came from 19 countries in four continents. The articles presented here were selected by the program committee whose members were Jose Balcazar (Polytechnic University of Catalunya) Francois Bancilhon (ALTAIR/INRIA) Marcos R. S. Borges (Universidade Federal do Rio de Janeiro) Ignacio Casas (Universidad Cat6lica de Chile) J. L. Encarna~ao (Zentrum fuer Grafische Datenverarbeitung) Hector Garcia-Molina (Princeton University) Michael Langston (University of Tennessee) Raphael Finkel (University of Kentucky) Tom Maibaum (Imperial College) Udi Manber, Chairman (University of Arizona) Michael Robson (Australian National University) The criteria for selection was based primarily on quality; we also considered relevance, clarity and the potential benefit to the community. In a time of great specialization, it is refreshing to see a conference devoted not to particular narrow fields but to all areas of computer science. Included are papers in algorithms, artificial intelligence, computer architecture, computer networks, databases, data structures, distributed systems, graphics and user interface, object-oriented systems, operating systems, programming languages, and the theory of computing. It was a pleasure reading high-quality papers in so many different areas of computer science.