Background: It has been documented that brain natriuretic peptide (BNP) was increased during cardiac ischemia and after myocardial necrosis. However, there are fewer data about hormone levels during percutaneous transluminal coronary angioplasty (PTCA) and off-pump coronary artery bypass graft (OPCAB). Methods: The purpose of this study was to investigate plasma pro-BNP in patients underwent PTCA or OPCAB, taking blood samples before and after both procedures. We studied retrospectively 30 subjects, 10 submitted to OPCAB and 20 submitted to PTCA. Blood BNP levels were measured the day before procedures and after 1, 3, and 7 days from the procedures. Results: BNP levels were not significantly different just before intervention (OPCAB group 310 짹 159.2 pg/ml vs. PTCA group 413 짹 371.2 pg/ml, p = NS). This difference was increased after 1 day (OPCAB group 1632 짹 1054.5 pg/ml vs. PTCA group 721 짹 960.3 pg/ml, p < 0.05) and after 3 days (OPCAB group 1073 짹 690.5 pg/ml vs. PTCA group 592 짹 463.1 pg/ml, p<0.05). However, there was no significant difference between two groups after 7 days (CABG group 350 짹 207.2 pg/ml vs. PTCA group 292 짹 189.1 pg/ml, p = NS). Conclusions: OPCAB could damage the myocardium during the immediate postoperative period comparing to PTCA, but these differences were decreased since time was going on. A further study is suggested to observe the effect to myocardium in long-term period.