Biotechnological methods can be used in dairy cow reproduction to increase reproductive potential and improve economic outcomes of milk production. Biotechnological methods widely used in reproduction include artificial insemination and embryo transfer, and more recently insemination with sexed semen, which makes it possible to control the sex of the offspring. This study presents an analysis of the effectiveness of the use of sexed semen in a selected herd of dairy cows. The results confirmed the effectiveness of sexed semen at increasing births of female calves. Sexed semen was most effective among heifers. In that group the fewest insemination doses were required for conception (1.54), and pregnancy after the first insemination procedure was noted in 52.2% of cases. The values of selected fertility parameters (calving-to-first-service interval, service period, services per conception, and rate of conception after first service) did not deviate significantly from recommended values in cows inseminated with sexed and unsexed semen. Among the group of cows inseminated with sexed semen, fertility parameters were significantly more favourable than in the group inseminated with conventional semen.