Twenty-five patients with systemic sclerosis and severe gastro-oesophageal reflux disease were treated with 20-80 mg omeprazole daily for up to 5 years. Efficacy of treatment was assessed by symptom score, by endoscopic and histopathological surveillance of the oesophageal and gastric mucosa, and by laboratory screening including serum gastrin concentration. Statistically significant relief of symptoms and healing of oesophagitis confirmed the efficacy of this treatment. However, complete healing of oesophagitis was not achieved in half of the patients due to residual gastro-oesophageal acid reflux. Repeated adjustments of the maintenance dose of omeprazole may be needed for this group of patients. From the safety point-of-view, nothing was observed to discourage the long-term use of omeprazole in this group of patients.