Among all diagnosed and treated lung cancers in Montenegro in 2009, 15.5 % were from Nikšić. The incidence rate was estimated to be around 42.5 per hundred thousand. In order to understand the role of radioactivity in initiating lung cancer the data on indoor radon concentrations obtained from earlier work coupled with that obtained in the present work for 226Ra, 232Th/228Ac, 40K and 137Cs from uncultivated soils, were used to estimate hazard indices. The risk factor for lung cancer due to radon was found to be significantly higher than excess lifetime cancer risk due to terrestrial radiation—outdoor. The stem of blackberry (Rubus fruticosus) was also analyzed for its radioactivity content, and showed soil–plant transfer factors for radium and caesium—from typical ranges for soil–plant transfer factors given in the UNSCEAR 2008 report.