Building on the 1997 work of Chezum and Wimmer, and the 1998 work of Lansford, Freeman, Topliff, and Walker, we estimated a hedonic hammer price model on a random and representative sample of 212 yearlings from the 1999 Keeneland September Yearling Sale. Explanatory variables representing day of sale, age of yearling, stud fee, racing performance of sire and dam, geographic origin of yearling, and yearling health information were statistically significant. In each model, we failed to reject the null hypothesis of no adverse selection; sellers who breed and race horses did not receive a statistically significant price penalty on their yearlings sold in this auction, compared to sellers who just breed horses.