Thoroughbred broodmares are the foundation of a successful racing operation. This study estimated the impact of breeding, racing, genetic, and market characteristics on broodmare auction prices. Data represent 298 broodmares in foal that were sold in Keeneland's 2005 sale. Prices were most responsive to the sire's stud fee and the broodmare's age, with pronounced day-of-sale effects. Overall valuation structure appeared similar to Neibergs' results using the 1996 data. Out-of-sample forecasts were far superior to naive forecasts, but were not accurate enough to use in isolation from other decision aids such as visual inspection of the horse.