Oesophagogastric ulcer (OGU) is a common condition in pigs, and may result in reduced production. Complications arising from oesophagogastric ulcer are one of the leading causes of death in post- weaning pigs (1). There are numerous predisposing causes of OGU, but their precise mode of action remains unclear (2). Recently, Helicobacter pylorus has been shown to play a significant role in the pathogenesis of gastritis and peptic ulcer disease in humans (3). Over the past few years many studies have attempted to clarify the link between the presence of spiral bacteria in the gastric mucosa and occurrence of OGU in swine (4,5,6). Conflicting results have been obtained. The objective of this study was to investigate spiral bacteria populations in the gastric mucosa of macroscopically healthy and ulcerated stomachs from Australian pigs.