Hypothesis: The technique used for repair of the esophageal hiatus during laparoscopic Nissen fundoplication can influence the likelihood of postoperative dysphagia. Design: A prospective double-blind randomized control trial. Setting: A university teaching hospital. Participants: A total of 102 patients with proven gastroesophageal reflux disease, undergoing a laparoscopic Nissen fundoplication were randomized to undergo fundoplication with either anterior (47 patients) or posterior (55 patients) repair of the diaphragmatic hiatus. Patients were excluded for the following reasons: they had esophageal motility disorders, required a concurrent abdominal procedure, had undergone previous antireflux surgery, or had very large hiatus hernias. Interventions: Laparoscopic Nissen fundoplication with anterior vs posterior hiatal repair. Main Outcome Measures: Independent assessment of dysphagia, heartburn, patient satisfaction, and other symptoms 1, 3, and 6 months following surgery, using multiple standardized clinical grading systems. Objective measurement of lower esophageal sphincter pressure, esophageal emptying time, distal esophageal acid exposure, and endoscopic assessment of postoperative anatomy and esophageal mucosa. Results: Symptoms of postoperative dysphagia, relief of heartburn, and overall satisfaction 6 months after surgery were not influenced by the hiatal repair technique. However, to achieve a similar incidence of dysphagia, more patients who initially underwent posterior hiatal repair required a second surgical procedure (6 vs 0 patients). The hiatal repair technique did not affect the likelihood of early postoperative paraesophageal herniation. Conclusion: Anterior suturing of the hiatus appears to be at least as good in the short-term as posterior suturing as a method of narrowing the hiatus during laparoscopic Nissen fundoplication.