Up to 30% of subjects undergoing Nissen fundoplication develop dyspeptic symptoms. Previous studies using the water load test have shown that functional dyspepsia patients have a diminished drinking capacity due to increased visceral sensitivity. Here we investigate drinking capacity and severity of symptoms in 9 patients with dyspeptic symptoms after fundoplication, 9 patients without symptoms after surgery, 18 functional dyspepsia patients, and 18 controls. The water load test was performed by having subjects drinking room-temperature tap water at a predetermined rate of 15 ml/min. The presence and severity of symptoms during the test were evaluated every 5 min using a Likert scale. We found that patients with dyspeptic symptoms after fundoplication had a significantly lower drinking capacity and higher symptoms scores than controls (P<0.05) but values similar to those of functional dyspepsia patients (P>0.05). In contrast, drinking capacity in patients without symptoms after surgery was similar to that in controls (P>0.05). These findings suggest that, as in functional dyspepsia, severe dyspeptic symptoms after Nissen fundoplication are associated with an impaired drinking capacity, reflecting visceral hypersensitivity or impaired gastric accommodation or both.