Calpastatin is an inhibitor of calpains which contributes to the post-mortem tenderization of meat.  Single nucleotide polymorphisms in the CAST gene were studied to have their effects on the meat tenderness in cattle wherein the A allele have shown positive influence compared to allele G in CAST 2959.  Objective of this study is to genotype Siquijor Native Cattle for CAST gene using PCR-RFLP technique. Hair samples were collected from 100 Siquijor Native Cattle located in Siquijor Provincial Veterinary Office and in Ubay Stock Farm, Bohol.  PCR primers that were used to amplify the fragment of CAST gene with size of 135bp were Forward: 5’-GAAAACGATGCCTCAGGTGT-3’ and Reverse: 5’-TGTGCCCATGCACAGTATT-3’.  DdeI enzyme was used to cut the amplified products and these were separated by electrophoresis on 3% agarose gel at 50V.  The results showed that A allele occurred at higher frequency compared to allele G with their frequencies were 0.65 and 0.35 respectively.  The genotypic frequencies obtained for AA, AG, and GG were 0.47, 0.37 and 0.16.  Chi-square test was done and the sample population did follow the Hardy-Weinberg Equilibrium.  The results show that PCR-RFLP is an efficient way to genotype CAST as gene marker for meat tenderness and determine the allelic and genotypic frequencies of CAST gene in Siquijor Native Cattle wherein there is presence of favourable allele A for meat tenderness.