MAIN FINDINGS FROM RADON INDOOR SURVEY IN MONTENEGRO. 
Recent residential radon survey in Montenegro revealed the national average annual radon activity concentrations: unweighted AM = 110 Bq m-3, GM = 58.3 Bq m-3, and population weighted (AM)w = 100.5 Bq m-3, (GM)w = 92.8 Bq m-3.  Based on (AM)w and dose conversion factor of 9 nSv per Bq h m-3, average effective dose from exposure to indoor radon at homes is estimated to be 1.58 mSv y-1.  222Rn was measured with CR-39 detectors for two consecutive six-month periods.  Radon concentrations are discussed with respect to their distribution, to the seasons, climate zones, urban and rural areas, house types, floor levels, basement and foundation slab.  Average radon concentrations are calculated for each municipality and for cells of a 10 km × 10 km grid, and corresponding radon maps of Montenegro are then produced.