Relation between risk of lung cancer and combined home and work indoor radon exposure was studied on example of population of Lermontov city (Stavropolsky Kraj, Russia). The city is situated in former uranium mining area. Case (121 lung cancer cases) and control (196 peoples free of lung cancer diagnosis) groups of the study included both exminers and populations that were not involved in the uranium industry. Home and work radon exposures were estimated using archive data as well as contemporary indoor measurements. The results of our study support conclusion on effect of radon exposure on lung cancer morbidity.