Clinical outcomes (as national clinical data) of isolated coronary artery bypass grafting have been successively reported, based on data registered in the Japan Cardiovascular Surgery Database, since 2013. In this study, we analysed the clinical results of isolated coronary artery bypass from 2017 to 2018 as a biannual report. Data from the Japan Cardiovascular Surgery Database on isolated coronary artery bypass performed in 2017 and 2018 were reviewed for preoperative characteristics, postoperative outcomes, and choice of graft material for the left anterior descending artery. Isolated off-pump coronary artery bypass was performed in 54.6% (n = 14,684) of all coronary artery bypass cases (n = 26,913), and graft material for the left anterior descending artery was the left internal thoracic artery in 76.4% of cases and the right internal thoracic artery in 19.0% of cases. Operative mortality was 1.5% in elective cases (on-pump coronary artery bypass 1.9% and off-pump 1.2%, p < 0.001), 7.4% in emergency cases (on-pump 10.2% and off-pump 4.3%, p < 0.001), and 2.5% overall. Postoperative morbidity was generally lower in off-pump coronary artery bypass. The severity of surgery with expected mortality, evaluated using JapanSCORE II, is increasing every year. Our findings suggest that short-term operative results for isolated coronary artery bypass are stable, and operative candidates are shifting to higher-risk patients.