Background: Medical x-ray exposures have the largest man made source of population exposure to ionizing radiation in different countries. Recent developments in medical imaging have led to rapid increases in a number of high dose xray examinations performed with significant consequences for individual patient doses and for collective dose to the population as a whole. It is therefore important in each country to make regular assessments of the magnitude of these large doses. Objectives: To calculate collective dose of the population as a result of radiation dose from diagnostic x-rays, thereby to estimate the annual incidence of cancer which would be reduced by the use of rare earth intensifying screen. Methods: Data on the number of diagnostic procedures using x-ray examination in year 2007 in nine governmental hospitals, excluding military hospitals, by body site were collected in Addis Ababa. The number of examinations of specific body site was multiplied by the average effective dose per examination to get the collective dose over the population. Based on International Commission on Radiological Protection (ICRP) the fatality risk of fatal cancers (5% per Sv) was estimated. Results: In this study, the annual collective dose over the population is 31.21manSv (0.0.42mSv per person). Based on ICRP fatality risk of 500 fatal cancers per 10,000 man-sieverts (5% per Sv), estimation of incidence of fatal cancers cases in year 2007 was 2 cases half of which can be reduced by adoption of rare earth screens. Conclusion: Although the use of ionizing radiation for diagnostic medical procedures is an acceptable part of modern medicine, there is also the potential for inappropriate use and unnecessary radiation dose to the patient, so the request of radiography must be justified. It is estimated that the adoption of rare earth screen technology might reduce the annual incidence of cancer which would be fatal after an average latency period of 18.4 years by half, hence this research recommended adopting rare earth screen technology in Ethiopia. [Ethiop.