1 De part ment of Phys ics, Fac ulty of Sci ence and Let ters, Uni ver sity of Kastamonu, Kastamonu, Tur key 2 Mugla Sitki Kocman Uni ver sity, Mugla, Tur key 3 De part ment of Phys ics, Fac ulty of Sci ence and Let ters, Cukurova Uni ver sity, Adana, Tur key 4 Turk ish Atomic En ergy Au thor ity, Lodumlu, An kara, Tur key Sci en tific pa per http://doi.org/10.2298/NTRP1802159TMea sur ing the nat u ral ra dio ac tiv ity lev els and ra don ex ha la tion rates (sur face and mass) in build ing ma te ri als is es sen tial to eval u ate the ex tent of ra di a tion ex po sure (ex ter nal and in ternal) for res i dents in dwell ings. Gamma-ray spec trom e try with a high pu rity ger ma nium de tector was used to mea sure the ac tiv ity con cen tra tions of 226 Ra, 232 Th, and 40 K in some build ing ma te ri als used in Tur key. More over, an ac tive ra don gas analyser with an ac cu mu la tion container was used to mea sure their ra don sur face and mass ex ha la tion rates. Re sults showed that the ac tiv ity con cen tra tions of 226 Ra, 232 Th, and 40 K var ied from 5.2 ± 0.6 (satin plas ter) to 187.0 ± 2.4 (gran ite) Bqkg -1 , 2.6 ± 0.8 (gyp sum) to 172.2 ± 7.6 (gran ite) Bqkg -1 and 12.3 ± ±.17.0 (sand) to 1958.0 ± 83.4 (brick) Bqkg -1 , re spec tively. Ra don sur face and mass ex ha lation rates var ied from 2.9 (mar ble) to 2734.6 mBqm -2 h -1 (gran ite) and 0.033 (mar ble) to 53.866 mBqkg -1 h -1 (gran ite), re spec tively. The ac tiv ity con cen tra tion in dex, in door ab sorbed gamma dose rate and cor re spond ing an nual ef fec tive dose were es ti mated and com pared with the rec om mended limit val ues. The re sults in di cated that the build ing ma te ri als sam pled presented no sig nif i cant ra dio log i cal risk.Key words: nat u ral ra dio ac tiv ity, ra don ex ha la tion rate, AlphaGUARD, an nual ef fec tive dose, build ing ma te ri al S. Turhan, et al.: Nat u ral Ra di a tion Ex po sure and Ra don Ex ha la tion Rate of .