An increased incidence of coeliac disease has recently been reported in patients with idiopathic dilated cardiomyopathy. This report deals with three patients with idiopathic dilated cardiomyopathy and coeliac disease who underwent clinical and laboratory evaluation to establish the effect of a gluten-free diet on cardiac performance. Two patients observed the gluten-free diet regimen very strictly, and, after a 28-month follow-up period, showed an improvement in echocardiographic parameters as well as in cardiological features and quality of life, as evaluated by the Minnesota Living with Heart Failure questionnaire and the Gastrointestinal Symptom Rating Scale questionnaire. The third patient did not observe the gluten-free diet and presented a worsening in the echocardiographic parameters and cardiological symptoms which required supplementary drug therapy. These preliminary data appear to suggest that the gluten-free diet may have a beneficial effect on cardiac performance in patients with idiopathic dilated cardiomyopathy.