Thirty-four patients with H2-blocker-resistant reflux esophagitis subsequently healed by 40 mg omeprazole daily entered a maintenance study with 20 mg omeprazole. In 31 evaluable cases the observation period was at least 12 months (mean 24 months). Esophagitis remained in remission in two thirds of patients despite dose reduction. Relapses of esophagitis occurred in 10 cases within six months, which rapidly healed by increasing the omeprazole dose to 40 mg. No further recurrence with 20 mg omeprazole was found later than six months. Peptic strictures primarily requiring repeated dilatation in six patients during healing with omeprazole did not reappear while on omeprazole maintenance. Major side effects that could be attributed to omeprazole were not observed. Gastrin levels remained within or slightly above the normal range in the vast majority. It is concluded that omeprazole maintenance treatment in severe reflux esophagitis is an effective and safe therapy.