The building materials are the sources of radon gas in the indoor air. The determination of radon and its progeny was performed by passive detection technique. Fifteenth commonly building construction materials used in Iraq were studied for radon concentration using the "sealed can technique" and CR-39 solid state nuclear track detectors (SSNTDs). The result of radon concentrations in the selected building materials ranges from 121.95Bq/m3 in Iraqi natural building stone, Iraqi Kashi and Egyptian ceramics to 383.3Bq/m3 in Turkish red granite. The radon surface exhalation rate and mass exhalation rate were ranged from 0.72Bq.m-2.h-1, 0.21Bq.kg-1.h-1to 2.3 Bq.m-2.h-1, 0.65Bq.kg-1.h-1 respectively.