A 46-year-old woman had features of acute pulmonary edema soon after taking hydrochlorothiazide (HCTZ) for the first time. Although 31 cases of HCTZ-induced pulmonary edema have been reported in the world literature since it was first described in 1968, little is known about this clinical entity. Because its presence may be underestimated or underreported, it must be considered in the differential diagnosis in any case of pulmonary edema in a patient taking HCTZ. It is important to review the pathophysiology and management of this rare but potentially life-threatening idiosyncratic reaction to a commonly prescribed drug.