The former Romania U-21 captain, earned his first cap in an exhibition match against Croatia on 20 November 2002. Because of the hepatitis rumours he lost for a few months the national team, but he was recalled for the friendly against Lithuania. On 23 May 2011, he was recalled for the Euro 2012 qualifying match against Bosnia and Herzegovina. However, following Victor Piturca's appointment as Romanian national team's coach, Sânmărtean was not called for the friendly against San Marino, despite his good shape. The Romanian fans started a petition called "Sânmărtean at the National team" on Facebook but it had no effect because he was not included in the squad once again. Nevertheless, Lucian was called up for the qualifying matches vs. Belarus and Albania in October 2011. He was also called up for Euro 2016 in France, making one appearance as Romania were eliminated in the group stage.