Cardiac involvement is frequent in myotonic dystrophy type 2 (DM2) with dilated cardiomyopathy and severe arrhythmias having been reported. Left ventricular non-compaction is a cardiomyopathy often associated with neuromuscular disorders. We report the case of a 61-year-old man with DM2 treated for 5 years for a suspected dilated cardiomyopathy. Echocardiography showed left ventricular non-compaction typical pattern, with prominent apical trabeculations and intertrabecular spaces perfused from ventricular cavity. MRI confirmed the diagnosis. Physicians should be aware of the risk of severe cardiac complications in DM2 patients. Left ventricular non-compaction diagnosis is often overlooked. Neurological examination should be performed in all patients with left ventricular non-compaction.