Determinants of stud fees are investigated for the first five years of a sire’s breeding career. In each year, more information about the quality of horse as a sire becomes available. Data is utilized with 163 sires entering the breeding shed between 2002 and 2005. Using Hedonic Price Analysis, it can be identified which determinants affect the stud fees to shift in price over a five year period. Results show strong evidence that a sire standing in the state of Kentucky is significant, and that a sires own racetrack performance is significant earlier on in his breeding career, with his progeny’s performance playing a key role in determining stud fee prices in later years.