Rosie and Roy is a lively, medium-up tune, alternating between straight-ahead swing on the A sections and a funky half-time feel on the B section. The melody starts with alto and trumpet taking the lead. The energy builds throughout the melody, as more parts are layered in, ultimately leading to the trombone solo. An angular interlude separates trombone and tenor sax solos. The tenor solo is a slow build, with backgrounds helping build intensity to the end. The shout chorus comes next, culminating in a drum solo, which leads the band back into the melody and a high energy ending.