ABSTRACT In this study an appropriate investigation was carried out to assess the geotechnical parameters and possible health risks to verify the suitability of Sahl Hasheesh (SH) area for the urban extension using GIS techniques. For this purpose, eighty-three bore holes were drilled at depths 20 m below the ground surface. Laboratory tests were performed on representative soil and rock samples to determine their physical, mechanical and chemical characteristics such as: grain size distribution, chemical analysis, Atterberg limits and point load strength. Also, airborne gamma-ray spectrometry was used for finding the three-radioactive elements (K, U and Th) concentrations near the ground surface of the study area. These concentrations were analysed for specific activity concentrations of 238U, 232Th and 40K radionuclide’s to calculate the exposure dose rate (DR) and annual effective dose rate (AEDR). The annual effective dose rate ranges from 0.2 mSv/y to 4 mSv/y under permissible level, so the study area is radioactively safe. GIS techniques were used to produce many geospatial layers of radioactive and geotechnical properties and integrated all these layers to build the geospatial urban extension model. The urban extension model illustrated that the ideal and good zones were observed in most of the study area. But, the marginal to poor zones were observed in the northwest and central regions of the study area. This model will be useful in the management and development of the area under study. In addition, it will represent a database in the future to decrease the hazards impacts on the construction.