Efforts by beef producers and beef packers to reduce carcass losses and to move the industry to a value-based marketing system have renewed their interest in the development of new electronic grading techniques for assessing beef carcass composition. A custom ultrasonic data acquisition system has been developed for the purpose of investigating the feasibility of beef tissue characterization. The unit developed is a compact, hand-held, six channel battery-operated data logger capable of sampling A-mode ultrasound signals at a rate of 15 megasamples per second. A custom epoxy encapsulated ultrasound transducer array was developed to fit the inner curvature of the thoracic cavity on top of the intercostal muscle between the 12th and 13th rib. Data collected by the ultrasound unit is temporarily stored in a handheld data terminal/computer for retrieval and analysis on a personal computer at a later time. Ultrasound samples from 39 carcasses were analyzed for backscatter energy content. The ultrasound records were partitioned into two groups based on the contact characteristics between the probe and tissue. Preliminary fat estimation in the longissimus dorsi muscle have resulted in correlation coefficients on two partitioned data sets of 0.81 and 0.82. Preliminary marbling estimation in the longissimus dorsi muscle have resulted in correlation coefficients on two partitioned groups of 0.59 and 0.70.