To identify smoking dependence predictors, 150 active smokers were interviewed. To assess tobacco dependence Fagerström's test was used. The potential associations between smoking dependence and some variables related to life style were investigated. In a case-control study design an induction period > or = 2 months was assumed. After estimating crude odds ratios, a logistic regression model was fitted. The dependent variable was dependence to tobacco smoking. In the multivariate analysis independent predictors, in addition to age, were: a) an earlier hour for starting smoking (OR: 6.08; 95% CI: 2.29-16.2), b) thinking that smoking avoids getting fat (OR: 4.36; 95% CI: 1.50-12.7) and c) not knowing any person with smoking-related pathology (OR: 3.75; 95% CI: 1.36-10.3). Exercise appeared to protect against smoking addiction (OR: 0.36; 95% CI: 0.13-0.98). The knowledge of these factors could help to avoid the development of smoking addiction.