In the 2005–06 season, Rumelange finished eleventh in the National Division. It was almost impossible for Rumelange to avoid fourth place, and they were pitted against FC Mamer in a relegation play-off. Rumelange lost on penalties, and were relegated to the Division of Honour. They won promotion to the highest level again at the end of the 2007–08 season.
US Rumelange have qualified for UEFA European competition four times. However, they have been generally unsuccessful; during their 1972–73 UEFA Cup campaign, they suffered a 21–0 aggregate loss to Feyenoord, a record defeat that has not been eclipsed in any UEFA cup competition. It has not been matched either, except for when, one year earlier, Chelsea had beaten Jeunesse Hautcharage by the same aggregate scoreline.