Background Myocardial infarction with nonobstructive coronary arteries ( MINOCA ) is a heterogeneous disease entity. Its prognosis and predictor of mortality remain unclear. This study aimed to compare the prognosis between MINOCA and myocardial infarction with obstructive coronary artery disease and identify factors related to all-cause death in MINOCA using a nation-wide, multicenter, and prospective registry. Methods and Results Among 13 104 consecutive patients enrolled, patients without previous history of significant coronary artery disease who underwent coronary angiography were selected. The primary outcome was 2-year all-cause death. Secondary outcomes were cardiac death, noncardiac death, reinfarction, and repeat revascularization. Patients with MINOCA (n=396) and myocardial infarction with obstructive coronary artery disease (n=10 871) showed similar incidence of all-cause death (9.1% versus 8.8%; hazard ratio [ HR ], 1.04; 95% CI, 0.74-1.45; P=0.83). Risks of cardiac death, noncardiac death, and reinfarction were not significantly different between the 2 groups ( HR , 0.82; 95% CI , 0.53-1.28; P=0.38; HR , 1.55; 95% CI , 0.93-2.56; P=0.09; HR , 1.23; 95% CI , 0.65-2.31; P=0.38, respectively). MINOCA patients had lower incidence of repeat revascularization (1.3% versus 7.2%; HR , 0.17; 95% CI , 0.07-0.41; P<0.001). Results were consistent after multivariable regression and propensity-score matching. In a multivariate model, several significant predictors of all-cause death of MINOCA were found, including the nonuse of renin-angiotensin system blockers ( HR , 2.63; 95% CI , 1.08-6.25; P=0.033) and statins ( HR , 2.17; 95% CI , 1.04-4.54; P=0.039). Conclusions Patients with MINOCA and those with myocardial infarction with obstructive coronary artery disease had comparable clinical outcomes. Use of renin-angiotensin system blockers and statins was associated with lower mortality in patients with MINOCA .