We wanted to examine the distribution of cancer by socioeconomic group in Sweden. For this purpose the 1960 Census population was followed up for the whole period 1961-79 by means of the Swedish Cancer Environment Registry. Cancer morbidity in five socioeconomic groups was analysed for each of 50 cancer sites. An association was found between several sites and particular socioeconomic groups. For instance, there are elevated rates of lung cancer and stomach cancer among blue collar workers; colon cancer and breast cancer among white collar workers and lip and stomach cancer among self-employed farmers. The overall cancer morbidity was close to the expected levels for all groups except self-employed farmers, who showed a marked deficit.