Aims To determine whether circulating levels of chromogranin A (CgA) provide prognostic information independently of conventional risk markers in acute coronary syndromes (ACSs). Methods and results We measured circulating CgA levels on day 1 in 1268 patients (median age 67 years, 70% male) with ACS admitted to a single coronary care unit of a Scandinavian teaching hospital. The merit of CgA as a biomarker was evaluated after adjusting for conventional cardiovascular risk factors. During a median follow-up of 92 months, 389 patients (31%) died. The baseline CgA concentration was strongly associated with increased long-term mortality [hazard ratio per 1 standard deviation increase in logarithmically transformed CgA level: 1.57 (1.44–1.70), P < 0.001], heart failure hospitalizations [1.54 (1.35–1.76), P < 0.001], and recurrent myocardial infarction (MI) [1.27 (1.10–1.47), P < 0.001], but not stroke. After adjustment for conventional cardiovascular risk markers, the association remained significant for mortality [hazard ratio 1.28 (1.15–1.42), P < 0.001] and heart failure hospitalization [hazard ratio 1.24 (1.04–1.47), P = 0.02], but not recurrent MI. Conclusion CgA is an independent predictor of long-term mortality and heart failure hospitalizations across the spectrum of ACSs and provides incremental prognostic information to conventional cardiovascular risk markers.