Study of indoor radon and thoron has been carried out in the health centres in Basrah Governorate-Iraq, using LR- 115 type II and CR-39 solid state nuclear track detectors (SSNTDs). In the present study the average value of indoor radon and thoron concentration of ranges from 59 Bq.m-3 in the first strip to 125 Bq.m-3 in Shatt Al-Arab strip for radon, and ranges from 9 Bq.m-3 in the first strip to 20 Bq.m-3 in Al Zubair and Al Hurtha strip for thoron. The average annual effective dose due to radon and thoron varies from 0.43 mSv.y-1 in the first strip to 0.90 mSv.y-1 in Shatt Al-Arab strip. This study is the first in this region.
