Nicorandil has been reported to have a preconditioning effect which suppresses the ST-segment shift or lactate production during coronary angioplasty in patients with stable angina pectoris. The present study investigated whether the preconditioning effect of ni-corandil affects troponin T (TnT) levels after coronary angioplasty. Twenty-four patients with stable angina pectoris were randomized to receive a 1-minute intravenous infusion of nicorandil (100 μg/kg) or normal saline. Five minutes later they underwent three 2-minute balloon inflations 5 minutes apart. The sum of ST-segment elevation in all leads (∑ST) was determined at the end of each balloon inflation. Serum levels of TnT were measured 6 and 18 hours after the procedure, and the higher value of the two measurements was compared between the groups. ∑ST decreased progressively during the three sequential balloon inflations in both groups and was less in the nicorandil group than in the control group. The TnT level after the procedure was significantly lower in the nicorandil group than in the control group (0.05±0.05 vs 0.11±0.10 ng/mL). In conclusion, pretreatment with intravenous nicorandil suppresses TnT release after coronary angioplasty as well as ST-segment elevation during coronary angioplasty, suggesting pharmacological preconditioning by nicorandil.