The aim of the present study was to analyse sexual activity levels of two purebred boars (pietrain and Duroc) in comparison with two-breed hybrid boars (Duroc♀ × Pietrain♂ and Pietrain♀ × × Duroc♂) and to assess the relationship between the ejaculate parameters and the sexual activity of the animals. the experimental material was constituted by 20 boars. sexual activity measurements were performed in 4 different collection periods for each boar. The first libido analysis was carried out during the first week of insemination use, followed by the next analyses after 3, 6 and 9 months of service. In parallel to the sexual activity analyses, ejaculates were collected to investigate ejaculatory efficiency, physical characteristics of the ejaculates and sperm morphology. It has been shown that the characteristics of sexual activity parameters are affected by the breed of the boar and the crossbreeding variant. Two-breed sires are quicker to leap onto the phantom as compared with purebred boars. Duroc♀ × Pietrain♂ boars are characterized by a short period of time between phantom mounting and ejaculation initiation. On the other hand, they yield ejaculates for a much longer time than hybrid Pietrain♀ × Duroc♂ boars and purebred Duroc and Pietrain boars. Hybrid boar ejaculates contain more spermatozoa and can provide more inseminationdoses than ejaculates of purebred boars. Ejaculate parameters are chiefly correlated with ejaculation time and copulation duration. In our study the ejaculate parameters (ejaculate volume, sperm concentration and sperm motility) in purebred boars mainly depended on ejaculation time and total copulation duration, whereas in two-breed hybrids they were more affected by the length of the period between phantom mounting and the start of ejaculation.