This study compared ultrasound measurements of body composition to carcass measurements of 145 heifers harvested in five groups. Results show that this technology can accurately measure URIBFT, UREA, and UMARB prior to slaughter. URIBFT was the trait that had the highest correlations and acceptable standard error of predictions (SEPs) and bias. The other two traits, UREA and UMARB, had lower correlation values but acceptable SEPs and bias. Real-time ultrasound is an accurate tool to measure body composition and can be used very effectively as a selection or sorting tool in the feedlot.