Gastroesophageal reflux disease (GERD) is caused by a mechanically defective lower esophageal sphincter (LES) and may be worsened by impaired esophageal peristalsis. The aim of this study was to evaluate the efficacy of medical treatment depending on the function of the LES and esophageal peristalsis. We studied 128 GERD patients with mild esophagitis. Group 1 (N = 26) consisted of patients with a normal LES and normal esophageal peristalsis. Group 2 (N = 63) comprised patients with a defective LES but normal peristalsis. Patients of group 3 (N = 39) had a defective LES as well as impaired esophageal peristalsis. The patients were continuously treated with omeprazole. Clinical evaluation and endoscopy were repeated after 3, 6, and 12 months. Recurrence of GERD was diagnosed if there was relapse of heartburn and/or esophagitis. The recurrence rate was 7.7% in group 1, 38.1% in group 2 (P < 0.05) and 79.5% in group 3 (P < 0.05). In conclusion, in GERD patients with a mechanically defective LES, especially in those with deteriorated esophageal peristalsis, antireflux surgery should be considered since medical therapy reveals a high recurrence rate.