Computed Tomography (CT) is increasingly used in abdominal imaging with a subsequent increase in the collective radiation dose. This is of particular concern, especially in young patients and in those with chronic diseases who undergo repeated CT studies including treatable cancers. The objective of this study was to establish the Computed Tomography National Diagnostic Reference Level (NDRL) In Paediatrics Radiography. 96 patient of CT abdomen and pelvis, 23% (22) of them were routine, 8% (8) tri-phase Abdomen, and 69% (66) CTKUB. The DRLS in 75% value was 637, 1095 and 514 mGy.cm Sequentially, Most of the patients were sent for the urinary tract problems especially renal stones, to check routinely without contrast agent, so DRLs (75%) for the abdomen in this study was proposed (575 mGy / cm). The data collected from 8 radiology departments .The patients were examined with the own department protocol using multi-slice CT (MSCT) dual slice ,8, 16 ,64 and 128 CT slice from different manufacturers. The range of patient dose per CT procedure was between 160 mGy.cm to 916 mGy.cm. Diagnostic reference level (DRL) was proposed for abdomen CT procedures. It is necessary to take a lot of precautions to reduce the radiation dose of children, especially direct exposure to the genital areas, by means of appropriate radiation protection, and the appropriate examination after consultation between the technician and the doctor and radiologist, and the existence of a reasonable interval between the examination and return.