Isolated left ventricular non-compaction (LVNC) is a rare genetic form of cardiomyopathy (CM) characterized by prominent left ventricular wall trabeculation and intertrabecular recesses communicating with the ventricular cavity. Clinical signs are variable, ranging from lack of symptoms to severe manifestations including heart failure, sustained ventricular arrhythmias, cardioembolism and sudden death. The diagnosis of LVNC is frequently missed, due to limited awareness in the medical community. Contemporary diagnostic sensitivity has been enhanced by the introduction of specific morphologic criteria by high resolution echocardiography and cardiac magnetic resonance. As a consequence, LVNC has been diagnosed more frequently in association with other disorders such as congenital heart disease or genetic CM. The clinical relevance of regional non-compaction in the context of other cardiac diseases is still uncertain. Recent evidence points to an overlapping genetic background encompassing LVNC, hypertrophic and dilated CM, suggesting a continuum of disease associated with sarcomere protein gene mutations. This concept may prove relevant to the understanding of common pathogenetic mechanisms of CM and offer novel research opportunities.