OBJECTIVE Coronary heart disease is the leading cause of heart failure (HF). The aim of this study was to assess the risk of readmission for HF in patients with acute coronary syndrome without previous HF or left ventricular dysfunction. METHODS Prospective study of consecutive patients admitted for acute coronary syndrome in 2 institutions. Risk factors for HF were analyzed by competing risk regression, taking all-cause mortality as a competing event. RESULTS We included 5962 patients and 567 (9.5%) experienced at least 1 hospital readmission for acute HF. Median follow-up was 63 months and median time to HF readmission was 27.1 months. The cumulative incidence of HF was higher than mortality in the first 7 years after hospital discharge. A higher risk of HF readmission was associated with age, diabetes, previous coronary heart disease, GRACE score> 140, peripheral arterial disease, renal dysfunction, hypertension and atrial fibrillation; a lower risk was associated with optimal medical treatment. The incidence of HF in the first year of follow-up was 2.73% and no protective variables were found. A simple HF risk score predicted HF readmissions risk. CONCLUSIONS One out of 10 patients discharged after an acute coronary syndrome without previous HF or left ventricular dysfunction had new-onset HF and the risk was higher than the risk of mortality. A simple clinical score can estimate individual risk of HF readmission even in patients without previous HF or left ventricular dysfunction.