Yepez was part of the Ecuadorian delegation in several international Championships and Tournaments: 16th Chess Olympiad of Tel Aviv 1964, 17th Chess Olympiad of Havana 1966, 18th Chess Olympiad of Lugano 1968, Open Tournament of Nice - 1974 (Capitan), Panamerican Tournament of Havana, 1968, II Tournament "Apertura" - Bogotá, 1970, Tournament "Ecopetrol - El Tiempo" - Bogotá, 1970, VIII Caribbean and Central America Zone Tournament FIDE, Bogotá – 1972.