In the bachelor's thesis we deal with radioactivity in building materials and theirgamma spectrometric measurements by two methods: semiconductor HPGespectrometry and scintillation NaI (Tl) spectrometry. The aim of this work is tosummarize information about the radioactivity, the radionuclides 40 K, 232 Th and 226 Ra,which are the main sources of radiation and to point out the legislative measures inthe field of radioactivity of building materials intended for the construction ofresidential buildings. The work also contains information about radioactive buildingmaterials that had been used the past and the consequences of their use. In thepractical part we deal with the measurements of the sample of natural stone used asa building material as a model sample to demonstrate the analysis methods. Theresults are also compared with the legislative requirements of the Slovak Republicand with the results from the available literature.