en Medical Physics Medical Physics تحقيق بديع Original Research <span style="font-weight: bold">Background: </span>Coronary angiography is a commonly performed diagnostic procedure with life saving benefits for the patient. However, this procedure involves relatively high radiation dose. The purpose of this study was to determine the average effective dose of patients undergoing coronary angiography and to estimate the associated radiation risk in terms of fatal malignancy. <span style="font-weight: bold">Materials and Methods: </span>Radiation doses received by 103 patients who underwent coronary angiography (CA) at one hospital of Yazd province in Iran were measured in terms of Kerma Area Product (KAP). KAP values were then used to determine the effective dose and the organ doses using the NRPB-S262 conversion factors and to estimate the radiation cancer risk based on the population averaged probability coefficients given in ICRP-60 and BEIR-VII report. <span style="font-weight: bold">Results:</span> A mean KAP value was found to be 29.15 ± 16.97Gy.cm2 and the estimated mean values of effective dose was 5.0 ± 3.18mSv. The dose of lung, esophagus, bone marrow, skin, stomach and female breast were 24.99±14.93 mSv, 14.01±9.47 mSv, 3.72±2.61 mSv, 2.9±1.8 mSv, 2.17±1.62 mSv and 1.46±0.32 mSv, respectively. The estimated total annual collective dose and caput dose were 17.52 man-Sv and 0.018mSv respectively. The frequency of examinations per 1000 population in Yazd was 3.5 which is lower than UK and the health care level I countries. Taking into account the ICRP risk factors, radiation dose arising from CA examinations could lead to 239 fatal cancers per million cases. <span style="font-weight: bold">Conclusion: </span>Although the mean values of effective dose found in this study was lower than most of the published results, however CA examinations should be justified. Iran. J. Radiat. Res., 2010 8 (3): 161-167 Coronary angiography, Kerma-area product, effective dose, radiation risk. 161 167 http://ijrr.com/browse.php?a_code=A-10-1-364&slc_lang=en&sid=1 F. Bouzarjomehri bouzarj_44@ssu.ac.ir 790031947532846001830 790031947532846001830 Yes V. Tsapaki 790031947532846001979 790031947532846001979 No