The COVID-19 pandemic has become a major public health crisis and increasing evidence demonstrates a strong correlation between obesity and severe forms of SARS-CoV-2 infections. Several mechanisms are advanced to explain this collusion. Obesity leads to an altered and delayed initial immune response, a chronic low-grade inflammation that promotes cytokine storm and a hypercoagulable state. Diagnosis is sometimes delayed by a tendency for these patients to avoid medical consultations and care complicated by weight and ventilation difficulties. In this article, we propose to review the mechanisms potentially involved in the collusion of these two pandemics.