The incidence of cancer of the oesophagus and stomach in the West Midlands region of England have been analysed for the 25 years 1962-86. Overall, cancer of the oesophagus is increasing (from 3.45 per 100,000 in 1962-66 to 4.37 in 1982-86) and stomach cancer is decreasing (19.22 and 16.54 respectively). However, when analysed by histological type and subsite the picture is very different. In oesophagus, squamous cell carcinoma shows only a slight increase whereas for adenocarcinoma the increase is highly significant (from 0.14 to 0.76). In stomach, cardia shows a very similar pattern to adenocarcinoma of oesophagus (increasing from 0.75 to 2.96) but pyloric antrum is decreasing (from 2.63 to 2.32). The rapid changes in investigative procedures over the period have resulted in increasing numbers with histological confirmation and subsite specification but despite these confounding factors, comparative analyses still indicate a real increase in adenocarcinoma of oesophagus and cardia. Although the incidence of both are greater in men than in women, the proportional rates of increase, particularly for cardia, are very similar in both sexes, indicating a common aetiological factor or factors. Analysis by social-economic group reveals that the increases observed are not uniform throughout the population but are relatively higher in professional classes (1 and 2).