Gastroesophageal reflux disease (GERD) is a chronic condition, with 50-80% of patients experiencing recurrence within one year of completing initial treatment. In patients with erosive GERD, proton-pump inhibitors (PPI) provide faster healing and symptom relief than do H2-receptor antagonists and have become the treatment of choice. Rabeprazole is a new PPI with demonstrated efficacy in both the acute and maintenance treatment of erosive GERD. The primary objective was to compare efficacy and tolerability of rabeprazole and omeprazole in preventing relapse of healed erosive GERD. Secondary objectives included comparison of efficacy in preventing GERD relapse symptoms and in maintaining quality of life. In this multicenter, double-blind, parallel-group study, 243 patients with healed erosive GERD were randomised to receive rabeprazole 10 mg once daily in the morning (QAM) (N = 82); rabeprazole 20 mg QAM (N = 78); or omeprazole 20 mg QAM (N = 83). Endoscopies were performed at weeks 13, 26, 39 (if clinically indicated), and 52, or when symptoms suggested recurrence. Corpus biopsies were performed at each endoscopy, and antral biopsies were performed at study entry and exit. Rabeprazole 10 mg and 20 mg QAM were equivalent to omeprazole 20 mg QAM for all efficacy parameters. At week 52, relapse rates in the intent-to-treat populations were 5%, 4%, and 5% for rabeprazole 10 mg and 20 mg and omeprazole 20 mg, respectively. All treatments were well tolerated. In conclusion, both rabeprazole 10 mg and 20 mg QAM are equivalent to omeprazole 20 mg QAM in preventing recurrence of erosive GERD.