Olkuska is a highly prolific sheep breed in Poland. Thanks to earlier identification of the genetic basis of its prolificacy, a mutation in the BMP-15 gene, we can use molecular biology tools to identify this causative mutation affecting prolificacy. In our research, we used the High-Resolution Melting (HRM) and Sanger sequencing methods to identify the genotypes of the studied animals. The result obtained by the HRM method is identical to those obtained by the sequencing method, which confirms the effectiveness of the HRM method and the possibility of quick and cheap identification of individuals with a FecXO mutation.