An analysis was made of the occurrence in Denmark of non-Hodgkin's lymphoma among men and women by socioeconomic group and detailed occupation, using a linkage between cancer registry data on incidence (1970–1980) and census data on industry and occupation (1970). No socioeconomic gradient in the risk for non-Hodgkin's lymphoma was found. Significantly increased relative risks were found in a number of detailed occupational groups including female physicians, female family workers in retail trade and transport; and male fitters, and gold, silver, and electroplate workers in metal industry. Also male cowmen experienced a significantly increased risk, whereas the risk was not increased for farming in general. Tabulations of clusters of detailed occupational groups suggested that groups with potential exposure to infections and chemical agents may experience an increased risk for NHL.