Studies on <transferrin polymorphism> in the flock of <long-wool sheep> from the State Animal Breeding Station in Bobrowniki were carried out. Genetic structure, of the population consisting of 6832 animals (171 rams, 3050 ewes and 3611 lambs) was examined. Inheritance of <transferrin gene> was traced and it is postulated to apply studies on transferrin polymorphism for parentage cintrol. In the studied sheep population the most frequent were alleles and BC, BD, CD and BB phenotypes. An analysis of transferrin alleles transfer from parents to their offspring in some cases showed significant divergence between the observed and expected numbers of offspring carrying particular genes. That concerned the phenotype AB in rams as well as AD and BE phenotypes in ewes. A theoretical probability of parentage exclusion in the examined stud of long-wool sheep estimated on the basis of the frequency of genes determining transferrin phenotypes was 43.18%.