To investigate the asbestos exposure level in non-occupational population and its relation to lung cancer, pulmonary asbestos fiber counts were observed with a modified alkali digestion method, in lung tissues from 65 random surgically treated lung cancer patients (42 males and 23 females) and that obtained from 107 random autopsy cases who died of either accidental death or acute myocardial infarction (44 males and 63 females) during 1987-1988. The patients and cases were all Hong Kong Chinese with no definite history of occupational exposure to asbestos. The non-lung cancer cases (NLCC) were divided into three groups based on different age ranges: 10 approximately, 40 approximately and 70 approximately years. The results showed that the medians of uncoated fiber counts (0, 32 and 52 fibers per mg dry tissue [f/mgDT] in the different age groups, respectively) increased in an age-dependent manner (P<0.01). However, the medians of coated fiber (asbestos body) counts were all 0 f/mgDT, with no statistically significant difference among the groups, showing a very low level of asbestos body burden in NLCC. In each age group, no difference in those counts between males and females was observed (P>0.05). Moreover, those counts in male lung cancer cases (medians of 62.5 and 17.5 f/mgDT, respectively) were greater than that in the control (32.5 and 0 f/mgDT, respectively) (P<0.01, P<0.05, respectively), however, regarding the female groups there was no statistically significant difference from the control. The results suggest that there is an environmental exposure to asbestos in Hong Kong Chinese, the level of which is, however, generally not sufficient to induce asbestos body. Environmental asbestos exposure in Hong Kong males may be one of the carcinogenic factors leading to lung cancer.