We summarize research results on association of cytochrome P450 2E1 (CYP2E1) genetic polymorphisms with the development of ecologically determined cancers. Cytochrome P450 monooxygenase enzyme system is involved in metabolic activation of procarcinogens, which is an important stage during normal cell transformation into a malignant one. Studies of association between CYP2E1 gene polymorphisms and the risk of cancer development are of particular interest, since the enzyme participates in bio-transformation of numerous procarcinogens. We place special emphasis on characterization of known CYP2E1 polymorphisms and analysis of their role in pathogenesis of various cancer types. Results obtained provide evidence on association of CYP2E1 genetic polymorphisms both with increased and decreased risk of development of malignant tumors. Ethnic and geographic peculiarities were also identified for frequencies of CYP2E1 variants distribution.