Objective : The Purpose of this study was to know effective radiation dose and lifetime attributable risk (LAR) of cancer associated with radiation exposure in patients with diagnostic coronary angiography(CAG) and percutaneous coronary intervention(PCI). Methods : The dose-area product (DAP) values were recorded from 60 patients with diagnostic CAG group and 58 patients with PCI group. A Monte Carlo based program (PCXMC) was used to calculate the effective dose from DAP values for each patient. LARs were estimated from models described in ���Seventh report of biological effects of ionizing radiation committee, USA (BEIR VII)'. Results : The mean DAP values was 53.7짹32.1 Gy․��� for CAG and 165.8짹95.6 Gy․��� for PCI. Mean effective dose were 1.2짹0.8 mSv in CAG, 3.9짹2.7 mSv in PCI. Organ dose to the lung was 2.2짹1.3 mSv in CAG and 6.7짹3.9 mSv in PCI. Female breast doses was 5.5짹3.3 mSv in CAG and 16.8짹9.7 mSv in PCI. LAR of cancer estimates were higher in women than men and higher in CAG than PCI ( 1/1,308 and 1/482 in women vs 1/1,508 and 1/553 in men). Conclusions : In conclusion, our study shows that LARs of cancer are not negligible and higher in women than men and higher in patients with PCI than CAG alone. Further studies are needed to elucidate the association between radiation dose and the risk of cancer in patients with cardiac catheterization and also medical personnel.