A novel skin dose monitor was used to measure radiation incident on maximal X-ray exposed skin during 135 diagnostic and 65 interventional coronary procedures. For the diagnostic studies (n = 135), mean skin dose was 180 +/- 64 mGy; for PTCA (n = 35), it was 1021 +/- 674 mGy, single stents (n = 25) 1529 +/- 601 mGy, and multiple stents with rotational atherectomy (n = 5) 2496 +/- 1028 mGy. The dose independently increased with more cine runs, more fluoroscopy, and greater patient weight. Physicians should consider the potential for adverse radiation exposure when planning coronary interventional cases and deciding on the X-ray mode and angles used.