This volume contains the proceedings of the LATIN 2000 International Conference (LatinAmerican Theoretical INformatics), to be held in Punta del Este, Uruguay, April 10-14, 2000. This is the fourth event in the series following Sao Paulo, Brazil (1992), Valpara so, Chile (1995), and Campinas, Brazil (1998). LATIN has established itself as a fully refereed conference for theoretical computer science research in Latin America. It has also strengthened...