In a Tobacco processing company, located in central Italy, both air nicotine and, one of its metabolites, the urinary cotinine were assessed, as part of the evaluation of the effectiveness of recently implemented technical preventive controls. Urinary cotinine measurements ranged from 9,63 to 234,09 microg/gr creat. in non-smokers and from 178,79 to 2476,19 microg/gr creat. in smokers. Urinary cotinine proved useful as an exposure biological index especially in terms of population monitoring. On the contrary, the meaning of the measured values were less clear in single workers, because of significant both intra- and inter-individual variability.