Calpains are a ubiquitous cytoplasmic cysteine protease, the activity of which is absolutely dependent on calcium. This proteolytic system degrades myofibrillar protein under post-mortem conditions and appears to be the primary enzyme in the postmortem tenderization process. In the present study a new single nucleotide polymorphism was found in the bovine CAPNS1 gene exon 11 coding for the 3'UTR. Transition C --> T at position 6536 was detected and identified using PCR-SSCP and DNA sequencing techniques, and then analysed with PCR-RFLP using MboII nuclease. The genotype frequencies and alleles distribution were studied in 190 bulls including, Charolaise, Hereford, Limousine, Simmental, Polish Red and Fresian breeds.