Erectile function is a haemodynamic phenomenon depending on the integrity of neurological, vascular, endocrinological, tissue (corpora cavernosa), psychological and relational factors; changes in any one of these components may lead to erectile dysfunction (ED). ED and its comorbid conditions share common risk factors such as endothelial dysfunction, atherosclerosis and metabolic and hormonal abnormalities. Furthermore, although cross-sectional studies have shown a clear age-dependent association between ED, diabetes mellitus, hypertension, metabolic syndrome (MetS) and cardiovascular diseases, longitudinal evidence has recently emphasized that ED could be an early marker of these conditions. Recently, the European Association of Urology and American Urology Association provided consensus guidelines for the management of ED patients. However, the metabolic aspect of ED is rather neglected or not sufficiently treated. In this study, more emphasis will be placed on the presence of ED comorbid metabolic factors. The primary and secondary goals of therapy, according to current guidelines and to prevent their clinical evolution, will also be provided. We review the concepts of metabolic diseases related to ED and their treatment. Criteria for the diagnosis and treatment of hypogonadism, metabolic and vascular disease related to ED were analysed. ED can mark the starting point for the evaluation and prevention of significant severe diseases (such as diabetes, MetS, dyslipidaemia, arteriosclerosis, hypertension, ischaemic cardiopathy, neuropathy, etc.) hitherto unknown by the patients. Most widely used criteria for the diagnosis and treatment of these diseases were reported. We suggest a clinical approach which allows the identification of metabolic and others systemic pathologies contributing to the development of ED. This approach may constitute an improvement in disease prognosis and either induce a spontaneous reduction of ED or facilitate its specific therapy.