Romero is the most capped goalkeeper in the history of the Argentine national team, playing over 90 times since his debut in 2009. He has represented Argentina at two World Cups and at three Copa América tournaments, finishing as runner-up in the 2014 FIFA World Cup, as well as in the 2015 and 2016 Copa América tournaments. He also was part of the team that won gold at the 2008 Olympics.