This study aimed to investigate the correlation of CYP1A1 and GSTM1 gene polymorphisms and environmental factors to familial aggregation of esophageal cancer (EC) among the Kazakh ethnic group in Xinjiang. CYP1A1 and GSTM1 gene polymorphisms were detected using peripheral blood from 86 subjects belonging to families with EC and 82 control subjects. Additionally, a questionnaire survey was conducted to ascertain environmental risk factors. Combined effects of CYP1A1 and GSTM1 gene polymorphisms and environmental factors in familial aggregation of EC were evaluated. Distribution frequencies of CYP1A1 MspI and GSTM1 genotypes between EC and control families showed significant differences (P = 0.002, P = 0.001). Contribution of interaction between CYP1A1 MspI mutant and GSTM1 deletion polymorphisms to familial aggregation of EC was significant, with OR = 3.571 (95%CI = 1.738-3.346). Logistic multivariate analysis indicated that familial aggregation of EC is correlated with 3 factors: drinking water, intake of fresh vegetables and fruits, and CYP1A1 MspI polymorphism (P = 0.005, P = 0.013, and P = 0.001). Sufficient intake of fresh vegetables and fruits (OR = 0.278, 95%CI = 0.137-0.551) protected against familial aggregation of EC, while drinking water (OR = 3.468, 95%CI = 1.562-6.551) and CYP1A1 MspI polymorphism (OR = 2.732, 95%CI = 1.741-3.886) were the risk factors. In conclusion, CYP1A1 and GSTM1 gene polymorphisms affect familial aggregation of EC among the Kazakh ethnic group in Xinjiang. River water intake and CYP1A1 MspI polymorphism were risk factors that likely contributed to high incidence of EC among families.