Increased permeability to sucrose has been recently shown to be a good marker of gastric mucosal damage in adults. In this study, the test was evaluated in 40 children consulting for persistent abdominal pain, and results were correlated with endoscopic findings. In 31 children the mucosa was considered normal, 3 had duodenitis and 6 had mild gastritis. Abnormal endoscopic finding were associated with increased sucrose excretion (MANOVA F=7:30;p=0.002). Children with mild gastritis had mean sucrose excretion that was twice that of controls (0.060±0.024 vs 0.029±0.018, respectively; p=0.019) and significantly higher that the group with duodenitis(0.037±0.013; p=0.038). Specificity and sensitivity of sucrose permeability test for detection of gastric damage were 90.3% and 83.3%, respectively. H. pylori was detected in 62.5% of children including all patients with mild gastritis, in 2 out of 3 with duodenitis and 17 out of 31 controls. No differences in sucrose excretion were observed in relation with the presence of H. pylori in the control group. These results suggest that urinary sucrose excretion is a good marker of mucosal gastric damage in children and may be used as a screening test in large groups of population.