The examination of 477 oil industry workers and office personnel (control) employed in the oil fields of the North of Tomsk and Tyumen regions has detected increased number of epithelyocytes with micronuclei and an elevated urine level ofbenzapilene in workers employed in oil production. Especially pronounced changes of the above parameters were observed in men with mutant alleles Val of CYP1A1 gene. An enhanced mutation process in oil production workers may be due to a resultant action of different factors on human genome. Involved may be both mutagens and factors of comutagenic nature. The results obtained in this study suggest a conclusion about urgent need of introduction of new scientifically validated criteria of selection of personnel for oil production in the North of the West Siberia. Health examination of the applicants must include genotyping.