Semen volume, sperm concentration, percentage progressive motility, percentage of abnormal spermatozoa and total number of sperm from boar ejaculates of different breeds and crossbred combinations from 23 AI centres of the Czech Republic were analyzed. Genetic parameters were estimated using multiple and single-trait animal models. The estimated heritabilities for semen volume and sperm concentration were around 0.20 whereas the estimates were somewhat lower for motility, percentage of abnormal sperm and total number of sperm. High negative genetic correlations were estimated between semen volume and sperm concentration (-0.68 for dam breeds, -0.69 for sire breeds) and between motility and percentage of abnormal sperm (-0.93 for dam breeds and -0.59 for sire breeds). Repeatabilities of 0.43 to 0.46, 0.37 to 0.38, 0.29 to 0.35, 0.42 to 0.50 and 0.29 to 0.30 were estimated for semen volume, sperm concentration, motility, percentage of abnormal sperm and the total number of sperm.