The characterization and radiological study of sludge technically enhanced naturally occurring radioactive materials (TENORM) waste samples collected from the production of oil and gas at Gabal EL Zeit eastern desert in Egypt were carried out using different analytical and radiological spectrometry. The sludge TENORM waste sample was fractionated to 3 different particle sizes (< 1mm, < 1.6mm, < 2mm) as well as bulk sample. Sludge TENORM waste (bulk and different sizes) samples were characterized by Fourier transform infrared (FTIR), energy dispersive x-ray, (EDX) and x-ray diffraction (XRD). The mean activities of bulk and different sizes for U-238, Ra-226, Pb-210, Ra-224, K-40 and U-235 were high levels of natural background radiation. Radiation hazard indices were calculated to assess the risk of these samples on workers and the environment. Some of the representative radiation indices such as radium equilibrium Raeq, absorbed dose rate Dabs, annual effective dose rate Dann, external and internal hazard index Hex, Hin, annual gonadal dose equivalent AGDE, activity utilization index AUI, excess lifetime cancer risk factor ELCR, representative gamma index Iᵧr, and alpha index Iα were derived and compared with the world average values. The results demonstrated that there is a harmful radiation effect posed to the public or factory workers.