For the GSTM1-GSTT1 interaction, we found that the GSTM1-GSTT1 combined null-genotype was significantly associated with COPD risks in overall populations (OR = 1.39, 95% CI: 1.15–1.67, p < 0.01), analysis of racial stratification showed no correlation. This evidence concerns the gene GSTM1 and chronic obstructive pulmonary disease.