The relationship between aflatoxins and liver cancer is well established. In addition the inhalation exposure to carcinogen aflatoxin B1 (AFB 1) is considerable. Genotoxic chemical is known to react with DNA either directly or after metabolic activation to form adducts, a step thought to be relevant with respect to chemical carcinogenesis. The presence and the amount of specific DNA adducts provide a good indication of chemical exposure and genetic damage resulting the exposure to carcinogens and account for same of factors affecting individual susceptibility to cancer. Analysis of DNA adducts requires that the sensitivity of the methods to be sufficient high to allow detection of about 1 adduct/109 normal nucleotides. Most suitable method is based in physiochemical technique such as HPLC. Because circumstantial epidemiological evidence suggests that AFB1 inhalation may cause primary lung cancer. We investigate AFB1 by HPLC in three different tobacco sources, and in 39 patients with compatible lung cancer or chronic bronchitis. The patients were divided by clinical manifestations in lung cancer (n: 25) and chronic bronchitis (n: 14). Twenty-three of 25 patients presented epidermoid lung cancer within smoking habit, and 2 of 25 presented adenocarcinoma without smoking habit. In chronic bronchitis group 12 of 14 cases presented smoking habit. The control PBS liquid was negative to AFB1; the different tobacco sources, a) Virginia of Jujuy, b) Brasilero and c) black of Salta presented AFB1 positive determinations respectively. The bronchial tissues obtained by lung biopsies presented positive AFB1 in lung epidermoid cancer at 0.68 +/- 0.82 mg/L. The adenocarcinoma presented AFB1 negative determinations. In chronic bronchitis patients with smoking habit (n: 12) presented AFB1 positive with a level less than the epidermoid lung cancer group, 0.21 +/- 0.109 mg/L, p < .025.