AB: The prevalence of developmental orthopaedic lesions was established for each joint in 142 Thoroughbreds subjected to routine radiography before they were presented to the yearling sales in Deauville between 1999 and 2001. The radiographic images were categorized using a previously established scale. 57% of the yearlings had abnormal radiographic findings (ARF). Preferential sites of ARF were the front fetlock with 23.2% of the horses with ARF, the hind fetlock with 10.6% of the horses with ARF on the dorsal aspect and 8.5% on the plantar aspect of the joint, and the carpus (5.6%). Racing performance were obtained for 92 two-years-old and 78 three-years-old horses. Parameters used to reflect racing performance were the age at the first race, the number of starts, victories and places, and earnings per year. The association between the presence of developmental orthopaedic lesions, and especially ARF, and the subsequent racing performance was studied comparing horses with ARF to a reference group of horses without any ARF. Most of the ARF seem to limit the racing performance or the duration of the racing career.