The objective of the present study was to evaluate relationships among recorded traits in a 100-day stationary performance test in warmblood stallions in Poland. The possibility of reducing the number of recorded traits was assessed as well. The data are from 582 warmblood stallions undergoing a 100-day test in 2002-2010 at two Polish training centres. The stallions were pre-selected on nine single conformation and movement traits and then inspected on nineteen performance traits scored by the head of the training centre, judging commission, and test riders. To establish the relationships within the data, entropy analysis was used. Entropy and conditional entropy in relation to the final assessment, as well as joint entropy, mutual information, and their quotient were estimated. High relationships between traits depend on their source of variability (head of training centre, judging commission, test rider). Variability over time of ranks for many traits is influenced by the differences in the genetic structure of the stallions tested in the last ten years. These estimates of conditional entropy can be helpful in derivation of weights for the recorded conformation, movement, and performance traits.