Martínez made his debut for Honduras in a November 2002 friendly match against Colombia and has earned a total of 49 caps, scoring 12 goals. He has represented his country in 8 FIFA World Cup qualification matches and played in all three of his country's games at the 2010 FIFA World Cup. He also played at the 2003 and 2009 UNCAF Nations Cups and the 2011 Copa Centroamericana, as well as at the 2009 and 2011 CONCACAF Gold Cups.