Results of the measurement of indoor radon and thoron carried out in and around Vijayanagar, Bangalore, India using passive detector technique is presented. Measurements were carried out using twin cup radon-thoron dosimeter using small strips of 12micron thick LR-115 type II nuclear track detectors. Measurements were carried out in 44 dwellings for a period of one year on a time integrated quarterly cycle to have the seasonal variation. After the exposure period, the detectorswere chemically analyzed using 2.5 N NaOHat 60 oC for a time of 90min and the etched detectorswere scanned by spark counter techniques. The estimated 222Rn and 220Rn levels in the studied locations showed the higher concentrations during winter season, in bath rooms, in concrete walls and in granite flooring houses. In this paper the authors have also made an attempt for the measurement of concentrations of indoor radon along with its distribution pattern based on constructionmaterial.