The objective of this study was to analyze the effect of the GSTM1 and GSTP1 genotypes on urinary 1-hydroxypyrene, a biomarker for exposure to polycyclic aromatic hydrocarbon. Urine samples were collected from coke oven workers at two time points (from 66 and 46 workers, respectively) and 1-hydroxypyrene was quantitated by HPLC chromatography. The genotype of GSTM1 and GSTP1 was determined by a PCR methods discriminating between GSTM1 present or absent and three different alleles for GSTP1. The mean value of urinary 1-hydroxypyrene was higher at both time points in coke oven workers with GSTM1 gene present compared to workers having the GSTM1 null genotype, but this difference was not statistically significant. The GSTM1 and GSTP1 genotypes were not significant parameters in a multiple regression analysis with urinary 1-hydroxypyrene as the dependent variable and with GSTM1, GSTP1, exposure group and smoking habit as explanatory variables. The biomarker 1-hydroxypyrene is not or only marginally influenced by the GSTM1 genotype. No systematic influence of the GSTP1 genotypes was found.