Background: Heart failure in the adult with adult congenital heart disease (ACHD) is a current topic due to its association with high morbidity and mortality and has been implicated as the leading cause of death in these kinds of patients. Purpose: This study reports experience of patients with ACHD and Acute Heart Failure (AHF) hospitalized at a teaching center specialized in cardiovascular disease in Latin America. Methods: A retrospective cohort study of patients with AHF who were hospitalized in the coronary care unit of a Latin-American teaching hospital from January 2006 to December 2018. Patients with ACHD were identified and their clinical characteristics and in-hospital evolution were analyzed. Results: During the study period, of 7,759 patients admitted with AHF, 181 (2.3%) had ACHD. Their median age was 34 years and 53.6% were men. Patients were grouped as follows: (Group I) left to right shunt 51.4%, (Group II) left ventricular outflow tract obstruction 17.7%, (Group III) outflow tract obstruction of the right ventricle 7.2%, (Group IV) conotronchal anomalies 3.9% and (Group V) miscellaneous group 19.9%. In general, history of previous surgery was in 28.2%, the frequency was higher in Group I and Group III (38.5% and 31.3%, respectively). Overall, all-cause in-hospital mortality was higher among patients with AHF- ACHD compared with patients without ACHD with AHF (23.2% vs. 17.8%; p=0.05). Unadjusted in-hospital mortality was not significant different across the five groups (21.5%, 28.1%, 7.7%, 42.9% and 25.0% for Group I, Group II, Group III, Group IV and Group V, respectively; p=0.41) (Figure 1). Conclusions: Adult patients with congenital heart disease and acute heart failure are a challenge in clinical and surgical management that entails a high in-hospital mortality. A high percentage of these patients are candidates for surgical treatment. Funding Acknowledgement: Type of funding sources: None. Figure 1