Objectives: The aim of this study was to evaluate the effect of occupational exposure in the occurrence of lung cancer. Method: Three-hundred lung cancer cases diagnosed between September 1, 1999, and September 31, 2007, and 300 healthy controls were enrolled in this case-control study. Life-long occupational history, gender, age, exposure to asbestos, comorbidities, and smoking status were collected. Results: The mean age of the 300 lung cancer cases was 60.3 ± 9.9 year (91.7% male and 8.3% female), and the mean age of healthy control group was 60.4 ± 10.5 year (95.0% male and 5.0% female). The most frequent histological types were squamous (172, 57.3%), adeno (69, 23.1%), and small cell (37, 12.3%). There was an increased risk of lung cancer occurrence among agriculture workers (OR=1.89, 95% Cl=1.17-2.98) ( p =0.009). Inorganic dust exposure (OR=1.81, 95% Cl=1.0-3.25) ( p =0.049) and organic dust exposure (OR=1.89, 95% Cl=1.0-3.59) ( p =0.05) were found to be related with high frequency of having lung cancer. Conclusion: Workers who had occupational exposure to organic and inorganic dust, especially in the agricultural field, had higher risk of lung cancer occurrence when compared with office workers.(J Occup Health 2013; 55: 301-306)