The objective of the study was to evaluate the effect of foreign studbooks in the breeding of warm-blood horses in the Czech Republic in the period 2000–2009. We included the following effects in our research: group based on the prevailing horse breed, year of start, sex, age and country of birth. We evaluated the effect of these parameters on the sports performance in show jumping competitions. The sports performance was based on the number of PPB points. The data were processed statistically using the general linear model (GLM). We discovered that the effect of these parameters was statistically highly significant. The HOLST1 group showed the highest performance (4.754 PPB points) and stands for individuals with a 100% proportion of the Holstein studbook. The second most successful group was KWPN1 (4.748). In the individual years of our investigations we found 22 statistically significant differences. For the entire period the number of PPB points was the highest in 2009 (3.420) and the lowest in 2000 and 2001 (2.678 and 2.779, respectively). The performance tended to increase in the individual years. We compared the performance of horses born in the Czech Republic and abroad and we discovered that performance was statistically higher in the group of imported horses. In terms of the effect of sex on the performance of horses in show jumping events the group of stallions showed the highest performance based on PPB points (3.842). In the experiment we estimated the effect of age on the sports performance; the group of 9-year-old horses achieved the highest performance based on PPB points (3.433).