The background ionizing radiation in some selected hospitals and diagnosticcentres in Owerri, Imo State, South-eastern Nigeria was measured using a portable Geiger Muller counter model GCA-04. The measured background radiation in all the environments considered ranged from 0.092±0.02-0.225±0.01 µSv/hr. The measured values were observed to be lower than the world average of natural background radiation of 0.2741 µSv/hr. This shows that the areas have low natural background radiation.