The Gastroesophageal Reflux Disease-Health-Related Quality of Life (GERD-HRQL) scale is a reliable, valid, responsive, and practical measure of symptom severity in patients with GERD. This type of scale is needed to determine effects of treatments and their comparison. This study defines the relationship between the GERD-HRQL score and the physiologic parameters of esophagogastroduodenoscopy, esophageal manometry, and 24-hour esophageal pH monitoring. Fifty-five patients referred for surgical evaluation of GERD answered the GERD-HRQL, a nine-item ordinal-scaled questionnaire. They were evaluated with esophagogastroduodenoscopy, esophageal manometry, and 24-hour pH monitoring. The relationships among these results were determined by linear regression analysis. There were no correlations between lower esophageal sphincter (LES) and any of the pH monitoring parameters (all r < 0.25, P > 0.2), esophagitis grade (r = -0.21, P = 0.2), nor any individual GERD-HRQL item score nor total score (all r < 0.2, P > 0.11). There were correlations between all the pH monitoring parameters and esophagitis grade (all r > 0.6, P < 0.001), but not with any of the GERD-HRQL item scores or total score (r < 0.3, P > 0.15). Six of the nine items scores and the total GERD-HRQL score correlated with esophagitis grade (all r > 0.4, P < 0.01). LES pressure is a poor indicator of symptom severity, the amount of reflux, and esophageal mucosal damage. pH monitoring-measured reflux and GERD-HRQL-measured symptom severity correlate well with mucosal damage. If the goals of GERD treatment are to relieve symptoms and reverse mucosal damage, the GERD-HRQL score and 24-hour pH monitoring are better outcome measures than the LES pressure. In an era of cost containment, the GERD-HRQL may be an adequate outcome measure.