PURPOSE: Many of the enzymes handling environmental factors are polymorphic and may confer variable susceptibility to renal cell carcinoma (RCC). Among those, the author studied genetic polymorphisms of CYP2D6 (B & T) and CYP1A1 in RCCs and controls in Korean. MATERIALS AND METHODS: Using 132 RCCs and 94 controls, first PCR products were obtained in 104 RCCs and 94 controls with CYP2D6, and 74 RCCs and 56 controls with CYP1A1. Res triction enzyme - BstN I/EcoN I for CYP2D6 (B & T), and NCo I for CYP1A1-digestion was followed to analyze constitutive DNA. RESULTS: In both RCCs and controls, no mutant allele of CYP2D6 (B & T) was detected and the susceptibility for occurrence of RCC was unable to evaluate. With CYP1A1 RFLP, homozy gous wild type (WW) was seen in 68 (52.3%; 37 RCCs, 31 controls), heterozygous mutant type (WM) in 54 (41.5%; 32 RCCs, 22 controls) and homozygous mutant type (MM) in 8 (6.2%; 5 RCCs, 3 controls). The odds ratios (95% CI) of RCC susceptibility for CYP1A1 genotype were 1.15 for WM and 1.36 for MM. Even though not significant statistically, higher tendency in MM presented. CONCLUSION: There is no association between susceptibility for the occurrence of RCC and genetic polymorphism of CYP2D6 (B & T) and CYP1A1.