A group of 86 persons (65 women, 21 men) working at the risk of ionizing radiation (IR) was examined for the levels of alpha 2-macroglobulin (alpha2-M), and compared to a group of age matched healthy population. Whereas the difference in men did not reach a level of significance, significant difference was assessed in women: in a subgroup older than 40 y exposed to the IR a rise of alpha 2-M levels was noted in correlation with the age. Multiple correlation coefficients showed a synergistic influence of both age and exposure to IR. The results are discussed from the point of view of the hypothesis that in exposed women a shifting realizes of usual old age changes to younger age group. A possibility is suggested to use the examination of alpha 2-M levels for preventive control of workers at the risk of IR.