Radon is an inert gas, and a naturally occurring radioactive material. Radon is produced by radium and uranium. Generated radon causes lung cancer through the inhalation. Therefore, If uranium contaminated soil is close to indoor spaces, residents may be exposed to this radioactive material(Radon). Generally, radon affects the first to third floors of buildings. But our research team has often detected high radon concentration in the indoor air of high-rise apartments. The reason for this is that building materials containing uranium and radium are brought into apartments. This study was conducted an investigation into the radon emission rate of building materials being used in South Korea. Also, our team conducted an investigation into the radon emission rate of gypsum tiles and concrete found in an apartment(17th floor apartment indoor radon concentration 5.03 pCi/L, Rad- 7(DURRIDGECo.USA)). Finally, we investigated the radon emission rate of bricks containing the soil near a uranium mine. The average radon emission rates of general building materials are as followings: (gypsum board : 0.20·h-1/kg, gravel : 0.05, gypsum tile : 0.02, indoor tile : 0.08, general brick : 0.02, red clay tile : 0.02, concrete : 0.11, uranium mine soil : 4.81). The results regarding the radon emission rate from a 17th floor apartment’s building materials are as followings: (gypsum board : 0.70, concrete : N/A). The results regarding the radon emission rate from bricks containing soil near a uranium mine was 0.19. This experiment indicates that gypsum boards show the highest radon emission rate among general building materials. In particular, the radon emission rate from the gypsum boards in a 17th floor apartment was 3.5 times higher than general gypsum boards. Overall the results suggest that building materials that possess high levels of uranium emit more radon gas than any other materials. South Korea has not established legal regulations on radon emission from building materials. However, the results of this study strongly suggest that it is of the utmost importance to manage the radon emission rate of building materials and control their usage before construction. Keywords : Radon, Building material, Soil, Gypsum board, Uranium mine