We had previously reported the association of the <i>NQO1</i>*<i>2/</i>*<i>2</i> polymorphism with a decreased risk for multiple myeloma (MM) in Koreans (odds ratio, OR, 0.24; 95% confidence interval, CI, 0.01–0.68). The associations of polymorphisms of other metabolizing enzymes (<i>CYP1A1</i>, <i>GSTM1</i> and <i>GSTT1)</i> with the MM risk were investigated in 116 Korean MM patients and 176 Korean controls using TaqMan allelic discrimination and multiplex polymerase chain reaction. The ORs for <i>CYP1A1</i>*<i>1/</i>*<i>2A</i> and <i>CYP1A1</i>*<i>1/</i>*<i>2B</i> genotypes were 0.43 (95% CI, 0.19–0.98) and 0.51 (95% CI, 0.26–0.98), respectively, which was significantly associated with a decreased MM risk. With regard to <i>CYP1A1</i> alleles, the OR for the <i>CYP1A1</i>*<i>2A </i>allele was 0.57 (95% CI, 0.326–0.995), which was also significantly associated with a decreased MM risk. However, null types of <i>GSTM1</i> and <i>GSTT1</i> polymorphisms were not associated with the MM risk. These results were different from those of a previous report on Caucasians which suggested the association of the <i>GSTT1</i> polymorphism with an increased MM risk and no association of <i>CYP1A1 </i>with the MM risk. The associations of polymorphisms of metabolizing enzymes with the risk for MM differed between Koreans and Caucasians, suggesting an ethnic variation in the susceptibility to MM.