With Monroe and Lester Flatt, Scruggs performed on the Grand Ole Opry and in September 1946 recorded the classic hit "Blue Moon of Kentucky"; a song that was designated by the Library of Congress to be added to the National Recording Registry, and later added to the Grammy Hall of Fame. The work schedule was heavy in Monroe's band. They were playing a lot of jobs in movie theaters all over the south, riding in a 1941 Chevrolet from town to town, doing up to six shows a day and not finishing up until about eleven at night. Lester Flatt said, "It wasn't anything to ride two or three days in a car. We didn't have buses like we do now, and we never had our shoes off". The self-imposed rule was to always get back in time to play the Grand Ole Opry in Nashville each Saturday night. Scruggs said of Monroe that "Bill would never let the music go down no matter how tired we were. If a man would slack off, he would move over and get that mandolin up close on him and get him back up there". Despite the group's success, Scruggs decided the demands were too great. He was single at the time, and the brief few hours on Saturdays that he made it home, it was just to pack his suitcase at the Tulane Hotel where he lived alone, then repeat the cycle—he had done this for two years. He turned in his resignation, planning to go take care of his mother in North Carolina. Flatt had also made up his mind to leave, but he had not told anyone. He later gave his two-week notice, but, before the notice was up, the bass player Howard Watts announced that he was leaving too. Despite Monroe's pleading, they left the band. Monroe thought Flatt and Scruggs had a secret understanding, but both men denied it. Monroe did not speak to either one for 20 years thereafter, a feud well known in country music circles.