The aim of the present study was to demonstrate the influence of boar breed and season on semen parameters. The research material consisted of 31 boars: Polish Large White (PLW), Polish Landrace (PL), and Duroc × Pietrain (D × P), aged 8 to 24 months. The analysed material consisted of 1390 ejaculates, collected during the period January 2010 to October 2012. Semen samples were assessed in terms of semen volume (mL), sperm concentration (× 106 m/mL), total number of sperm (× 109), total number of live sperm (× 109) and number of insemination doses obtained from one ejaculate (n). In winter, an increase in sperm concentration was observed for the PLW breed. Moreover, an increase in the volume of semen produced for this breed was noted in summer and autumn. Differences between breeds for the total number of sperm and total number of live sperm were observed for the winter and spring periods. The largest semen volume was noted for the PLW breed (276.4 ± 9.66 mL). However, in the analysis of other sperm parameters, boars of this breed demonstrated the poorest results. The highest insemination dose was obtained from breed D × P in winter (26.0 ± 0.51). Correlation analyses indicated that PLW and D × P boars are the least resistant to higher ambient temperatures, and in summer and autumn this resulted in a reduction in sperm concentration (–0.26 and –0.20, respectively).