U.S. feeder cattle markets discriminate among a wide variety of animal characteristics such as weight, sex, breed, grade, and age. In recent years, concern has been expressed that price premiums paid for steers over heifers no longer reflect estimated differences in their feedlot performance or carcass value [2,8]. Another question is whether observed regional differences in steer-heifer price differentials are justified. The sources of feeder price differentials by sex are investigated and variations in these differentials across time and space dimensions are analyzed. The results provide preliminary evidence on the efficiency with which feeder markets establish price spreads.