Results: GSTM1 null genotype was found to be significantly associated with a 1.6-fold increased risk of lung cancer (OR = 1.60, 95%CI = 1.01–2.52, p = 0.0491), whereas no significant association was observed with GSTT1 null genotype and combined GSTM1 and GSTT1 null genotype. The gene discussed is GSTM1; the disease is lung cancer.