Hypertrophic cardiomyopathy (HCM) is the most commonly diagnosed cardiac disease in cats. The phenotype varies from mild focal thickening to severe concentric hypertrophy at the left ventricle. Two separate myosin binding protein C (MYBPC3) mutations have been identified in Maine coon cats (A31P and A74T) and one in Ragdoll cats. All three of them seem to cause familial HCM in an autosomal dominant pattern. The purpose of this study was to investigate the presence of these three mutations in population cats of different breeds with HCM in Sweden. The results may show if HCM is present in the absence of these mutations.