The aim of this work was to analyze gestation lenght of sows in relation to numbers of stillborn piglets and losses of piglets from birth to weaning before repopulation (status A) and after repopulation (status B). 160 sows were included in the experiment. The repopulated group of sows showed longer gestation, particularly 116.90 ± 3.62 days, compared to sows before repopulation, with 115.31 ± 1.48 days of gestation. At the same time with longer gestation, lower losses of piglets were recorded (1.18 ± 1.44 piglets and 7.48 ± 8.62 %) from birth to weaning contrary to shorter gestation with highly statistically significantly (P ? 0,001) higher losses, particularly 2.05 ± 1.43 piglets and 17.29 ± 10.49 %. With shorter gestation lenght, also number of stillborn piglets increased (1.88 ± 1.55 piglets and 13.45 ± 10.33 %). With longer gestation, the number of stillborn piglets decreased (1.21 ± 1.53 piglets and 7.18 ± 8.34 %) with highly and very highly statistically significant difference (P ? 0.01; P ? 0.001 respectively). The results indicate that repopulation of sows positively influences numbers of stillborn piglets and losses of piglets before weaning.