In this, thesis work we present the natural radionuclide concentration of Zenzelima at Tana basin near to Bahir Dar city. The RS-230 radiation detector spectrometer was used to determine the natural radioactive concentration of active elements such as 238 U, 232 Th and 40 K respectively. The recored were performed for the soil activity concentrations ranged from 11.1 to 43.2 Bqkg 232 Th, and 125.2 to 845.1 Bqkg 1 for 40 1 for 238 U, 19.9 to 64.5 Bqkg K. Absorbed dose rates in air outdoors were calculated to be in the range of 27:2 93:5 nGyh 1 with an overall average value of 44.4 nGyh 1 . The study showed an annual e ective dose equivalent in the range of 0:17 0:57 mSvy 1 . A comparison of the measured values with the corresponding worldwide average values shows that the activities of natural radionuclides in the studied samples are below the world average activity values. 1 for