The validity of 24-h oesophageal pH recording was studied in 100 consecutive patients who had gastro-oesophageal reflux (GER) symptoms and had indications for a 24-h pH recording. The aim was to explore the relationship of patient symptoms, endoscopic findings and histopathological analysis of oesophageal mucosa with the findings in pH recording. Among these patients with typical GER symptoms, the multiplicity of symptoms or their nature did not differentiate them, but in all groups abnormal amounts of reflux were present, as compared with usual reference pH recording values. Yet, among these symptomatic patients, the macroscopic severity of oesophagitis and histologically defined oesophagitis were related to increased abnormality of 24-h pH recording. The results suggest that 24-h pH recording of the oesophagus gives a good indication of the severity of gastro-oesophageal reflux disease and, as such, superior to patient symptoms.