The proposed biological mechanisms for exercise-induced pulmonary haemorrhage (EIPH) are many and varied. Better knowledge of risk factors should lead to achievable measures to reduce the incidence. To identify risk factors associated with epistaxis following racing in UK Thoroughbreds, to gain possible insights into the pathogenesis of the condition and to investigate the association between epistaxis and race finishing position. The association of epistaxis occurring on UK racecourses between 1996 and 1998 with a wide range of race-, horse- and start-level variables was examined in multivariable mixed effect logistic regression analyses. Four multivariable analyses were conducted, one for all race types considered collectively and one each for flat, hurdle and steeplechase race types considered separately. Risk of epistaxis was significantly increased for hurdle and steeplechase race types compared to both flat and National Hunt flat races. In 3 of the 4 final models, there was a significant biological trend for increasing risk of epistaxis with increasing ground hardness ('going') and accumulated years spent racing. However, in flat races epistaxis was such a rare outcome (0.33 cases per 1000 starts) that this subset analysis had insufficient power to measure the detectable effect of 'going' as statistically significant. Horses with epistaxis were significantly more likely to have a poorer finishing position than those without blood at the nostrils. Findings were consistent with the theory that locomotory impact-induced trauma contributes to exercise-induced epistaxis. Further validation of this hypothesis through application of similar methods to endoscopically visible EIPH and through biomechanical studies is warranted. Knowledge of significant risk factors should allow formulation of practical measures, such as track watering, to reduce the risks of EIPH and epistaxis in racehorses.