Mutagenicity of cigarette smoke is one of the major health concerns related to smoking. Reduction of the components comprising mutagenic activity in cigarette mainstream smoke can be expected to bring about reduced risk of smoking. The purpose of this study is to isolate mutagenic compounds and to investigate the relative contribution to allover mutagenicity of smoke to find clues for the effective elimination of the components. Cigarette smoke condensate (CSC) was obtained from total particulate matter (TPM) of mainstream smoke, and several fractions fractionated from CSC were made by combination of cation exchange chromatograph and reverse-phase chromatography. The mutagenic activity of these fractions was assessed using Salmonella mutagenicity assay with S. typimurium TA98 strain in the presence of metabolic activation system (S-9). The fractions isolated by cation exchange and reverse-phase column showed relatively high mutagenic activity. The basic and hydrophilic fraction 9 showed approximately 33% of mutagenic activity of CSC and its specific activity was 2,459 revertants/mg TPM. These results suggest that hydrophilic cation exchanger and/or other adsorbents possessing similar properties may be used to remove the mutagenic compounds from mainstream smoke.