Analyses of cancer incidence data from nine areas of the United States revealed steadily rising rates from 1976 to 1987 of adenocarcinomas of the esophagus and gastric cardia. The increases among men in this period ranged from 4% to 10% per year, and thus exceeded those of any other type of cancer. In contrast, there were relatively stable trends for squamous cell carcinoma of the esophagus and slight declines for adenocarcinoma of more distal portions of the stomach. Adenocarcinomas of the esophagus and gastric cardia disproportionately affected white men and rarely occurred among women. By the mid-1980s. among white men, adenocarcinomas accounted for about one third of all esophageal cancers, while cardia cancers accounted for about one half of all stomach cancers with specified subsites. The rising incidence rates and similar demographic patterns point to the need for investigation into the causes of these poorly understood cancers.