Hyponatremia is a possible complication secondary to major surgeries, occurring in approximately 4% of the patients.1 The mechanism of the decreased sodium levels is thought to be the syndrome of inappropriate secretion of antidiuretic hormone (SIADH). However, even minimally invasive procedures, such as endoscopic procedures, may cause SIADH.2 Herein, we report a rare case of SIADH secondary to the endoscopic procedure.