Background: Lectin-like oxidized low-density lipoprotein receptor-1 (LOX-1) is implicated in atherosclerotic plaque vulnerability. It is shed, in part, by proteases and released as soluble LOX-1 (sLOX-1), which is a specific and sensitive biomarker of acute coronary syndrome (ACS). The present study explored if sLOX-1 can also predict prognosis after ACS. Methods and Results: ACS patients undergoing emergency percutaneous coronary intervention and measurement of circulating sLOX-1 were followed (median: 896 days). Among 94 patients, 13 had ACS recurrence or died (re-ACS/death group). None of age, sex, lipid profile or prevalence of diabetes, smoking or hypertension was significantly different between the re-ACS/death group and the event-free survival group. Circulating sLOX-1 levels, but not those of high-sensitivity C-reactive protein (hs-CRP) or troponin T (TnT), were significantly (P<0.005) higher in the re-ACS/death group than in the event-free survival group. Kaplan-Meier survival curves showed that ACS patients with sLOX-1 values in the highest quartile or tertile had more frequent and earlier ACS recurrence or death. Receiver-operating characteristic curves for prediction of re-ACS or death showed higher sensitivity and specificity for sLOX-1 (area under the curve for sLOX-1, hs-CRP and TnT: 0.764, 0.658 and 0.524, respectively). Conclusions: Circulating sLOX-1, a diagnostic biomarker of ACS, also predicts ACS recurrence or death.