Of 2,600 coronary operations performed from August 1983, to December 1988, two ischemic reactions of the inferior wall immediately after operation were observed. In both patients the right coronary artery was either dissected or revascularized intraoperatively. Under the diagnosis of postoperative spasm both patients had reangiography three hours after surgery. Right coronary artery spasm was demonstrated in both patients. After intracoronary injection of calcium channelblockers the spasm resolved completely. Patient 1 demonstrated a small inferior infarction during control angiography, patient 2 remained free of a myocardial infarction. The possible causes of coronary spasm during or after surgery are discussed. The diagnosis and an approach to therapy are outlined.