Chromosome aberrations were analyzed from peripheral lymphocyte cultures of 21 men and 19 women who had been exposed to environmental cadmium, and 11 controls (9 men and 2 women). The average cadmium level in the urine of the Cd-polluted group was 3.32 micrograms/l for men and 3.83 micrograms/l for women. There were significant differences in chromosome aberration frequencies between the Cd-polluted and non-polluted groups. The number of individuals with relatively high aberration frequencies (greater than or equal to 5%) in the Cd-polluted group was greater than in the controls. Individuals with a high cadmium content in urine (greater than or equal to 3 micrograms/l) had higher aberration frequencies and more severe aberration types in comparison with the low-cadmium group (less than 3 micrograms/l). There were significant correlations between chromosome aberration frequencies and urinary cadmium content (r = 0.463). The linear regression equation was determined. Considering the conflicting results in other published reports, it is hard to say that the conclusion that cadmium only acts synergistically to enhance the mutagenicity of other compounds present in the environment is correct. According to our study, environmental cadmium cannot only induce chromosome aberrations but also increases the chromosomal aberration frequencies and the frequency of severe aberration types.