The activity concentrations of uranium, thorium and potassium can vary from material to material and it should be measured as the radiation is hazardous for human health. Thus first studies have been planned to obtain radioactivity of building material used in the Isparta region of Turkey. The radioactivity of some building materials used in this region has been measured using a gamma-ray spectrometry, which contains a Nal(Tl) detector connected to MCA. The specific activity for Ra-226, Th-232 and K-40, from the selected building materials, were in the range 17.91-58.88, 6.77-19.49 and 65.72-248.76 Bq/kg, respectively. Absorbed dose rate in air (D), annual effective dose (AED), radium equivalent activities (Ra-eq), and external hazard index (H-ex) associated with the natural radionuclide are calculated to assess the radiation hazard of the natural radioactivity in the building materials. It was found that none of the results exceeds the recommended limit value. (C) 2010 Elsevier Ltd. All rights reserved.