We report on a paediatric case of autosomal dominant polycystic kidney disease, where myocardial hypertrophy proved a consequence of noncompaction of the ventricular myocardium. Deletion of PKD1 and PKD2, the genes responsible for polycystic renal disease, has been linked also to disorganized myocardial arrangement in experimental animals. Two adults with polycystic kidney disease and myocardial hypertrophy in whom a careful diagnostic workup led to a diagnosis of non-compaction of the ventricular myocardium have been reported in the literature. Nephrologists must be aware of the possible association between the two diseases because early recognition of the disease may help in preventing the onset of complications.