In this study, Groundwater samples were collected from twenty five wells and Radon concentrations were measured as part of a water-quality. These samples were taken from the municipal wells in the southern region of Gaza Strip (Rafah and Khanyonis). The samples were collected from different location covering most of the region that represent the southern part of Gaza Strip. Twelve wells from Rafah Governorate and thirteen wells from Khanyonis Governorate were taken and all these wells were used for domestic water. Each sample was duplicated to determine Radon concentration.