Among all possible sources of radiation dose to human beings, inhalation of radon and its progeny contributes a lot to the dose. High concentrations of radon and its daughter products in mines have led to an increase in the incidence of lung cancer among mine workers. There is correlation of lung cancer risk for the people working inmines. For the long termmeasurements more than 100 dwellings were selected for the measure of radon, thoron and their progeny concentrations using solid state nuclear track detectors. By knowing the track density of films through spark counter, and sensitivity factor for bare, filter and membrane; the concentrations of radon, thoron and their progeny were calculated. The radon, thoron and their progeny levels were found to vary fromwall to wall. The variationmay be attributed due to random distribution of radioactive rock used in the construction of buildings. The radon, thoron and their progeny levels in different types of floorings, wall, room and building material are well within the admissible limit.