Using two interrelated observation indices--chromosomal aberration and micronucleus analysis in peripheral blood lymphocytes to reflect damages of genetic material, were used to observe the status of genetic material damage in male smokers at the same time. The results showed that there were significant increases in hyperpolid cell rate, chromatid and chromosome aberration rates, total aberant cell rate and frequency of micronucleated cells as well as micronucleus in smoking group when compared to non-smoking group. This findings showed that cigarette smoking is one of the important mutagenic factors which caused damage to human genetic materials.