Coronavirus disease (COVID-19) is caused by SARS-CoV2 virus, which causes serious respiratory illness such as pneumonia and lung failure. It was first reported in Wuhan, Hubei, China in December 2019 and rapidly spread globally, becoming a pandemic infection in March 2020. Although symptoms highly heterogenous (from absence of manifestations to severe respiratory acute failure), patients with metabolic associated diseases often resulted in worse COVID-19 outcomes. This study aims to investigate the association between metabolic diseases and COVID-19 severity, defining the possible molecular mechanisms that possibly determine the link between the two diseases and the worsening of COVID19 phenotype. In particular, we will define the role of the main biological processes that may function connecting metabolic alterations to SARS-CoV2 infection; hyperglycemia, immune system deregulation, ACE-2 receptor modulation, inflammatory response. The impact of metabolic disorders on the prognosis of COVID-19 have major implications in public health especially for countries affected by a high incidence of metabolic diseases.