The Spanish Purebred (PRE) horse is the most important breed in Spain due to its census, and its historical and socio-economical importance. PRE horses are evaluated according to their sportive performance, conformation and temperament within the Breeding Scheme of this breed. Individuals (grouped by sex and age) are subjectively evaluated by judges in horse-shows. The aim of this study is to ascertain the influence of environmental factors (related to the animal and the show) influencing the scores and rankings. Up to 8 morphological, 2 movement and 3 functional (only in 3 years-old males) traits are scored by show-judges using a numerical scale from 1 (the worst) to 10 (the best). Here, 3 composite traits characterising morphology, movement and functional performance of the individuals have been constructed using partial scores. The effects of the coat colour, age, sex, stud, show-horse, year of celebration, state, total number of animals, number of judged animals and the order within age-sex group on judgements have been tested besides some interactions between these effects. The statistical significance of the analysed effects on the scores given by the show-judges is discussed.