Symptomatology was evaluated in 304 patients referred for 24 h oesophageal pH monitoring. Of several symptoms thought to be related to gastrooesophageal reflux disease (GORD), only heartburn (68% vs 48%) and acid regurgitation (60% vs 48%) occurred in more of the patients with GORD (as determined by pH monitoring) than of those with normal pH monitoring. When heartburn or acid regurgitation clearly dominated the patient's complaints, they had very high specificity (89% and 95%, respectively) but low sensitivity (38% and 6%) for GORD. A third of the patients reported such inconclusive symptomatology at history-taking that no preliminary diagnosis about the presence or absence of GORD could be made. In the remaining 200 patients, a clinical diagnosis by history had a sensitivity of 78% and specificity of 60%. A discriminant analysis of symptoms was inferior to a history taken by an experienced gastroenterologist.