Cancer incidence in Estonians who took refuge in Sweden in 1944-1945 has been compared with that in the total Swedish population and that among Estonians in Estonia in 1974-1985 using data from the Swedish and the Estonian countrywide population-based cancer registries. The vast majority of the Estonian immigrants studied had been living in Sweden for 30 years when the follow-up with respect to cancer incidence started in this investigation. In spite of the long residence in Sweden, differences in cancer incidence could be observed between these immigrants and the total Swedish population. The age-standardized incidence of stomach cancer was higher in the Estonian migrants than in the total Swedish population (SIR = 1.6 and 2.1 for males and females, respectively). Breast cancer incidence was lower in the migrant women (SIR = 0.75) and lung cancer incidence higher in migrant men (SIR = 1.5). An increased incidence of colorectal cancer was also found for both sexes in the migrant population (SIR = 1.4 for both males and females). A comparison between Estonians in Estonia and the total Swedish population revealed that the cancer incidence for the Estonians was lower than expected at age 70 and over. Male lung cancer and stomach cancer showed a higher incidence in the Estonian population than in the Swedish and in the migrant populations. The migrant population showed an intermediate incidence relative to Estonians in Estonia and the entire Swedish population. The colon-cancer risk in Estonian migrants to Sweden was higher than the risk for Estonians in Estonia and for the Swedish population. This contrasts with most findings in the present and other studies on intermediate risks of migrants compared to the risks in the country of origin and in the new country of residence.