Background and objective GSTM1 takes part in the metabolism of environmental pollutants such as benzopyrene other polycyclic aromatic hydrocarbons and anticancer drugs and so on. The study aims to investigate the relationship between the gene polymorphism of GSTM1 and chemotherapy as well as to study the effect to survival of Chinese patients with lung cancer. Methods The genotypes of GSTM1 were examined with polymerase chain reaction in 137 primary lung cancer patients accepted chemotherapy. Results GSTM1 -null genotype frequency was 58.4%(80?137). The frequency of non-null GSTM1 genotype was 41.6%(57?137). The frequency of GSTM1-null genotype was 69.05%(58?84) in the response group of chemotherapy and 41.51%(22?53) in the non-response group of chemotherapy. They were significantly different (P=0.001). In the patients with platinum chemotherapy, the frequency of GSTM1-null genotype was 65.43%(53?81) in the response group of chemotherapy and 42%(21?50) in the non-response group. There werestastically differences in them (P=0.0025). For the advanced cases, GSTM1 -null genotype frequency was 70.13% (54 ? 77) in the response group of chemotherapy, 41.51% (22?53) in the non-response group of chemotherapy respectively and they were significantly different(P=0.001). When the chemotherapy was effective, the survival time of patients in squamous carcinoma and small cell carcinoma with non-null GSTM1 genotype (the median survival times were 42 months and 14 months respectively) were longer than those with null GSTM1 genotype (the median survival times were 6 months and 7 months respectively)(P0.05. When chemotherapy was not effective, the median survival time were not significantly different (P>0.05). Conclusions The effect of chemotherapy of GSTM1-null genotype patients was better than that of GSTM1-postive genotype patients. The chemotherapy effect of the cases with null GSTM1 type was better than those with non-null GSTM1 type when the patients accepted platinum chemotherapy. When the chemotherapy was effective, the survival time may be related to the histological types and GSTM1 genotypes.