The purpose of this study was to estimate the genetic parameters of biokinematic variables in Spanish Purebred (SPB) horses in order to select those of sufficient interest to be measured in the pre-selection of the animals for possible inclusion in the breeding programme. Kinematic analysis of 130 SPB horses 4.6+/-1.5 years old were recorded at the trot (4m/s) on a treadmill. Genetic parameters were estimated using VCE software and a bivariate mixed animal model including age and stud as fixed effects and animal additive genetic effect and residual error as random effects. In general, heritabilities were high (0.33-0.88). The angular variables presented the lowest heritabilities, whereas the maximum height of the fore-hoof and the duration of swing phase in the hindlimb gave the highest scores. Genetic correlations were also very high, so it was possible to reduce the number of breeding programme characteristics to stride duration, hindlimb swing phase duration, range of stifle and elbow angles, minimal angle of carpus, and minimal retraction-protraction angle of the hindlimb.