The mortality of 622 men who worked for at least one year in the production, polymerization, and processing of styrene at a chemical site in the United Kingdom during the period 1945-1974 was surveyed up to the end of 1978; 3 072 male manual workers at the same site but unexposed to styrene were also studied. A statistically significant excess of lymphoma deaths was found in the exposed population, and two of the three deaths observed occurred in men less than 40 years of age. The small number of deaths and the lack of any evidence for an association with duration or level of exposure to styrene are reasons for interpreting this result cautiously. However, the otherwise normal pattern of mortality in the exposed population and the absence of any excess of lymphomas in the reference group lend some support to suggestions that exposure to styrene may be associated with lymphomas in man. An analysis of cancer registrations for the exposed population revealed no further cases of lymphoma but identified one case of lymphatic leukemia. An excess of laryngeal cancer registrations was found. As this effect has not been previously postulated and because of the small number of registrations, too much weight should not be attached to this one observation.