In this study, we evaluated the relationship between the degree of gastro-oesophageal reflux and the rate of gastric emptying and determined the variability of gastric emptying in children. The reproducibility of radionuclide imaging for the presence and grading of gastro-oesophageal reflux was also examined. Twenty-eight children less than 2 years of age participated in the study. For assessment of variability, all subjects underwent two scintigraphic studies. For each study, the number of reflux episodes and gastric emptying half-times were recorded. The amount of reflux was graded according to the classification suggested by Blumhagen. Patients with grade 1 reflux were considered low-grade refluxers, while patients with grade 2 or 3 reflux were considered high-grade refluxers. The level of reflux for each patient was based on the highest reflux grade recorded in either study. Of the 28 patients, 19 had reflux in at least one study. Ten patients had high-grade and nine patients low-grade reflux. All patients but one with high-grade reflux had the same grade of reflux in both studies (90%). Of nine patients with low-grade reflux, three had the same grade in both studies. The mean half-time was significantly higher for high-grade than for low-grade refluxers (P < 0.05). For subjects with low-grade reflux, this value did not differ significantly from that of non-refluxers (P > 0.05). Our results show that patients with high-grade gastro-oesophageal reflux had prolonged gastric emptying. The inter- and intra-subject variability of gastric emptying in children appeared to be low. Reproducibility for the presence and grading of gastro-oesophageal reflux by the radionuclide method was good, with the highest value being for the diagnosis of high-grade gastro-oesophageal reflux.