Backgrounds: Smoking is accepted as a main risk factor for lung cancer. It has different importance in individua! histological types. This study analyses smoking in relation to different histological types of lung cancer cases from the Šumperk district. Design and Subject: A case-control study has been ušed for analysis of smoking in relation to histological types of 451 lung cancercases and 37.769 controls. MethodsandResults: Odds ratio has been ušed to compare the relationshipbetween smoking and histological types of lung cancer both inmen and women. Odds ratio 17,9 and 18,6 wasfound forsquamous and small cell types whiles treached 7,4 and 9,4 for adenocarcinoma and large cell types. Conclusion: This study confirms that smoking represents a more pronounced risk factor for squamous and small cell carcinoma than for adenocarcinoma and large cell type of lung cancer.

        Key words: lung cancer, smoking, histological types, case-control study, odds ratio