Aims: We examined whether a plasma ceramide-based risk score (CERT1 score) is associated with an increased risk of all-cause mortality and nonfatal myocardial infarction in patients with known or suspected coronary artery disease (CAD). Methods: We studied 167 ambulatory patients who consecutively underwent stress myocardial perfusion scintigraphy (MPS) for clinical reasons in 2017 (at baseline) and then followed for a median period of 73 months (interquartile range: 56-77 months). At baseline, three distinct plasma ceramide concentrations (i.e., plasma Cer[d18:1/16:0], Cer[d18:1/18:0] and Cer[d18:1/24:1]) and their specific ratios to Cer(d18:1/24:0) were measured by a targeted liquid chromatography–tandem mass spectrometry assay, both before and after stress MPS, to calculate the basal and post-stress CERT1 risk score. The primary outcome of the study was a composite of all-cause death or nonfatal myocardial infarction. Results: During a median follow-up of 73 months, a total of 50 events occurred (26 all-cause deaths and 24 nonfatal myocardial infarctions). There was a significant association between basal CERT1 risk categories (high vs low risk) and the risk of developing the primary composite outcome (unadjusted HR 1.78; 95%CI 1.02-3.14). This risk remained significant after adjustment for age, sex, smoking, diabetes, prior history of CAD, LV ejection fraction and stress-induced inducible myocardial ischemia on MPS (adjusted HR 2.28, 95%CI 1.17-4.41, p=0.015). Almost identical results were observed for post-stress CERT1 risk categories. Conclusions: Basal and post-stress CERT1 risk score is strongly associated with an increased long-term risk of all-cause death or nonfatal myocardial infarction in patients with established or suspected CAD.