Nasal desmopressin (DDAVP) is a commonly prescribed antidiuretic hormone (ADH) analogue used for treatment of diabetes insipidus, polyuria and nocturnal enuresis. Although it is generally well tolerated, it can cause severe electrolyte imbalance. Numerous reports exist on cases of mild to moderate DDAVP-induced hyponatremia, yet few reports describe severe hyponatremia (Na<115 mEq/L). We present a case of a 52-year-old woman with nearly symptom-free, DDAVP-induced hypotonic hyponatremia of 104 mEq/L following a gastrointestinal illness. We describe the appropriate correction of her hyponatremia and conclude by raising awareness of the potential for severe cases of desmopressin-associated hyponatremia, even in the rather symptom-free patient.