**Abstract**

The current coronavirus disease (COVID-19) pandemic, caused by the severe acute respiratory distress syndrome coronavirus 2 (SARS-CoV-2) is a serious public health concern worldwide. Over time, it became more evident that COVID-19 can affect multiple endocrine organs and hormonal substances, eventually negatively affecting patients with COVID-19 infection. The mechanism underlying hyponatremia in patients with COVID-19 is not fully understood but many postulated hypotheses have been tested. The exact mechanism of hyponatremia following COVID-19 infection also has yet to be established. The management options in those patients need to be taken carefully and to be directed to the primary disease. In this chapter, we summarize the association of syndrome of inappropriate anti-diuretic hormone secretion (SIADH) induced hyponatremia with COVID-19 infection.

**Keywords:** COVID-19, SIADH, hyponatremia, extrapulmonary organs, angiotensin-converting enzyme 2 (ACE2)
