Members of the European Network of Cancer Registries (ENCR) provide population-based data on cancer incidence for some countries and regions of Europe. These were supplemented by estimates in order to provide comparable information on cancer incidence and mortality in the 15 member states of the European Union (EU). The estimated numbers of new cases of cancer (excluding nonmelanoma skin cancer) in 1990 were approximately 706,900 in men and 644,200 in women. Approximately 497,500 men and 398,200 women died of cancer in the same year. The main sites of incident cases in men were lung (21%), large bowel (13%), prostate (12%), bladder (7%) and stomach (7%). For women, the predominant sites were breast (28%), large bowel (15%), lung (6%), uterine corpus (5%) and stomach (5%). The overall incidence rates for males were highest in continental Western Europe (France, The Netherlands, Austria, Luxembourg, Belgium, Germany and Italy) while the rates of Greece, Portugal, Sweden, Ireland, Spain, Finland, the U.K. and Denmark were below the average value for the EC. Rates for females were highest in Northern and Western Europe, with the exception of France, which had a relatively low rate for females, in common with Greece, Spain and Portugal. The geographical variations in incidence of the major cancers are discussed in relation to risk factors. The estimates show the substantial burden of cancer in European Union populations, but there are also indications of effects of past preventive measures and there is scope for further intervention. Cancer registries are an important source of information for cancer control since they provide population-based incidence and survival statistics. These, along with mortality data, are required to obtain a full picture of the frequency of cancer and its effects at the population level. Some 44% of the EU population is covered by registries. The European Network of Cancer Registries aims to standardise the information provided by existing registries and to provide practical assistance to those in development.