The current study aims to determine the background radiation level in Mosul University Campus using multiple technologies, portable detector type Inspector EXP+ containing Geiger-Mueller tube, NaI(Tl) and CR-39 detectors. The portable detector was used to measure the dose rate (Dexp.) at 1 m height from the ground. The radioactivity concentrations of 40K, 222Rn, 226Ra, 232Th, the dose rate (Dcal.) at 1 m height from the ground, radium equivalent activity (Raeq), gamma index (Iγ), alpha index (Iα), external hazard index (Hex), internal hazard index (Hin) and radon exhalation rate (E) were calculated. An empirical equation between the field and the laboratory measurements of the dose rate in air (Dcal., Dexp.) and other equations between (Iγ, Dcal.), (Iγ, Raeq), (Iγ, Hex) and (Raeq, Hex) were found.