Martínez made his debut for Honduras in a July 2001 friendly match against Ecuador, in which he immediately scored a goal, and has earned a total of 35 caps, scoring 16 goals. He has represented his country in 11 FIFA World Cup qualification matches and played at the 2007 and 2009 UNCAF Nations Cups His international breakthrough however came during the 2001 Copa América, when Honduras surprisingly ended third and Martínez scored both goals in the historic win over World Cup runners-up Brazil.