The main natural radionuclides U-238, Th-232, U-235, and the members of their decay chain were studied in detail. P-type HPGe detector was used for specific activity concentration measurements. This work is stressed on the distribution of these natural radionuclides in forty five sedimentary rock samples collected from west Gabal Adediya, southwestern Sinai, Egypt. The average activity concentrations for 238U, 232Th, and 40K ranged between 104.38 ± 42.16 Bq⁄kg and 4507.41 ± 202.96 Bq⁄kg, 9.97 ± 2.2Bq⁄kg and 143.83 ± 14.53 , and 60.02 ± 3.78( Bq)⁄kg and 1567.34 ± 9.11 Bq⁄kg with an average value of 1016.31 ± 83.87 Bq⁄kg, 87.39 ± 10.10, and 804.53 ± 7.32 Bq⁄kg respectively. The obtained values were higher than that of the recommended values. Radiological hazard parameters were estimated based on the activity concentrations of 226Ra, 232Th, and 40K to find out any radiation hazard associated with these sediments. The radiological hazard parameters such as: absorbed gamma dose rates in air(D_air ), annual effective dose equivalent (AEDE), external hazard index 〖(H〗_ex) internal hazard index 〖(H〗_in), the annual gonad equivalent dose (AGED), and excess lifetime cancer risk (ELCR), were calculated and compared with internationally approved values and the recommended safety limits.