Objective Satiety is the perception of satisfied fullness and represents a summation of neural and hormonal influences. Satiety can be assessed by drink tests, including water load. The objective of our study was to confirm the difference in water load volume between nonobese control children and children with functional dyspepsia (FD), children with irritable bowel syndrome (IBS), and obese children. Methods A total of 158 children ages 6 to 13 years participated in the study. There were 43 children with FD, 25 with IBS, 44 obese children, and 46 nonobese age-matched control children. Subjects drank as much water as possible in 3 minutes or until their stomachs felt full. Results Children in the FD and IBS groups drank less water than did the nonobese controls; the obese children drank more water than did the nonobese controls. The water load test demonstrated high specificity but poor sensitivity in predicting children with FD. Conclusions A water load test offers a simple, noninvasive research tool to measure satiety. Children with chronic abdominal pain drank less than nonobese control children; however, the water load test did not discriminate between FD and IBS. Obese children drank more water than the other groups, suggesting the possibility of an underlying abnormality in the perception of satiety.