Data in a regional cancer registry covering a population of 5 million and with an efficiency of registration of over 95% have been used to examine incidence trends in oesophageal and gastric carcinoma. In the West Midlands Region of the UK, during the period 1962 to 1981 the age standardised incidence of gastric carcinoma decreased by 20%. However, an analysis by both histological type and detailed site reveals that while the incidence of distal lesions is diminishing, the incidence of adenocarcinoma of the oesophagus and cardia is increasing. The proximal and distal lesions also exhibit marked differences in social class distribution and sex ratio. The results strongly suggest that the aetiological factors involved for cardia and adjoining sites are different from those for pyloric antrum.