The aim of this thesis was to compare the reproductive performance of sows on two farms within a selected company, which is engaged in breeding pigs. There were observed phenotypic level of selected reproductive parameters, namely the total number of piglets born, number of piglets born alive and number of weaned piglets. These reproductive performance were also compared depending on the order of litters and the length of pregnancy. The evaluation of the results we can say that the best reproduction performance were achieved in 2014 on a farm A, namely 15,00 pcs of all born piglets per litter. Live born and weaned piglets per litter were found most in 2015 on a farm B, namely 12.56 pcs / litter of live born piglets and weaned piglets - 11.67 pcs / litter. In comparison reproductive performance in the sequence of litter in the number of live born piglets were the best third and subsequent litters on the farm A - 14.66 piglets per litter. The most live born piglets were found in the third and subsequent litters on the farm B - 12.58 piglets per litter. The highest number of weaned piglets were found again in third and subsequent litters, namely 11.64 piglets per litter on the farm B. The evaluation of influence of the length of pregnancy on the reproductive performance is obvious that the best results in all parameters was achieved at a length of pregnancy in the interval from 111 to 113 days. All born piglets per litter were found 15.2 pcs / litter on the farm A and live born piglets per litter were the most on the farm B - 12.55 pcs / litter. The most weaned piglets were found on the farm B - 11,70 pcs / litter. Losses of piglets from birth to weaning were recorded at least on the farm A in 2015 - 5.73% of piglets born alive and on the farm B in 2014 - 6.69%. Depending on the order of litter was the best result achieved at the farm and for sows in the second litter, when losses were recorded only 0.09% of piglets born alive. The best result of losses in relation to the length of pregnancy was achieved on farms A 3.24% at the length of pregnancy in the interval from 117 to 119 days