The goal of this study was to evaluate the distribution of blood lead level (B.L.L.) in a general adult population aged between 20 and 79 years non professionally exposed to lead, and to verify the influence on B.L.L. of demographic variables (i.e. sex and age), behavioural habits (i.e. alcohol consumption and cigarette smoking), and anthropometric variables (i.e. body mass index--BMI). We studied the distribution of B.L.L. by explorative analysis method (E.D.A.), which showed that data did not follow a Gaussian distribution. Distribution fit to normality was determined by Shapiro-Wilk test, that identified the natural logarithm of B.L.L. as the best transformation in order to normalize the parameter. According to literature data, sex appears one of the most important variable in determining B.L.L. In both sexes we found a direct relation between B.L.L. and age. Alcohol consumption emerged as the third most important variable that influences B.L.L. BMI and cigarette smoking do not influence data distribution.