Although a rare tumor form, there is evidence that the incidence of esophageal adenocarcinomas is increasing in Western Europe and the US. The aim of this nationwide population-based study was to describe the secular trends in the incidence rates of adenocarcinoma and squamous-cell carcinoma of the esophagus over a 28-year period from 1960 to 1987. The Swedish Cancer Registry, complete to more than 95%, was used to identify the cases. The percentage verified by histology rose from 89% to 98%. The age-standardized incidence rate of adenocarcinoma increased in males from 0.5 per 10(5) in 1960-63 to 1.1 per 10(5) in 1984-87, corresponding to an average annual increase of 1.5%. In females the incidence remained stable around 0.2 per 10(5). The age-standardized incidence rate of squamous-cell carcinoma in males increased from 2.9 to 4.0 per 10(5), corresponding to an average annual increase of 1.0%. In females the rate decreased from 1.4 to 1.2 per 10(5), corresponding to an annual average decrease of 0.5%. The male/female ratio was 4.6 for adenocarcinoma and 2.7 for squamous-cell carcinoma of the esophagus. Since the incidence rates of squamous-cell carcinoma of the esophagus and of adenocarcinoma seem to be rising, there is a great need for well-planned analytical epidemiological studies of these tumor locations, taking the histological type into consideration.