Smoking is a public health problem because consumption is growing and exhibits earlier ages of onset; in terms of the biological processes of smoking, several genes have been identified whose variants are related to this phenomenon. The aim of this study was to evaluate the relationship between rs6801272 and rs680244 polymorphisms in genes CYP2A6 and CHRNA5, respectively, with the consumption of tobacco. For this, a case study was conducted (smokers-ex smokers versus controls) matched by age and sex, as well as considering starting age and number of cigarettes per day. The monomorphic locus rs6801272 was found in the study population, presenting the T allele associated with normal metabolism of nicotine; and the rs6801272 locus was found to be polymorphic, but the relationship of this genetic variation with cigarette smoking (OR 3,2) or the capacity to abandon smoking (OR 5,3) was not established; it was not possible to establish a correlation between the genotype and the number of cigarettes per day (R2 = 0,001) or genotype and age of onset (R2 = 0,015). In conclusion, a relationship between the genetic variants studied and consumption, capacity of quitting, number of cigarettes per day and age of onset was not detected.