In persons with Down's syndrome (DS), congenital cardiac defects are frequent, including atrioventricular canal defect, ventricular septal defects and atrial septal defects. However, in patients with this syndrome, hypertrophic cardiomyopathy is very rare because only five cases have been previously reported in the literature. We have identified one male 52-year-old with DS and non-obstructive cardiomyopathy. The echocardiogram of this patient showed a prevalent apical involvement of the left ventricular hypertrophy as previously reported in two adult patients with DS and hypertrophic cardiomyopathy. Although rare, hypertrophic cardiomyopathy can occur in individuals with DS and, in adult patients, the apical form is frequent.