The evaluation of genetic variability suggests that the maximum number of known ancestors was 14 generations in the population of the Přeštice Black Pied breed. On average, all animals had known ancestors up to the fifth generation. The average total inbriding was 4.41%, with an average increase of up to 1.58% between the last generations. In recent years, the coefficient of ibriding has been steadily increasing with the higher proportion of inbriding acquired over the last four generations. The influence of inbriding on the observed traits was statistically significant but low. A higher effect was observed in reproductive signs (especially in the meantime and all piglets born). The correlation coefficient between new and old inbriding was 31%.