Real-time ultrasound (RTU) images were collected on 170 Angus sired steers. These steers had routine carcass data collected, as well as lean mass weights after round fabrication. Lean weight in the round was determined by adding the peeled knuckle, inside round, and outside round weights together. There were four significant independent variables (P < .05) used to predict lean in the round from live measurements. They were: live weight (WT), ultrasound fat thickness between the 12th and 13th ribs (UFT), ultrasound ribeye area between the 12th and 13th ribs (UREA), and gluteus medius lean depth (GM).