A growing number of Congenital Heart Disease (CHD) patients will achieve adulthood. We aim to assess the characteristics, clinical course, and outcomes of Adult CHD (ACHD) patients attending the Emergency Department (ED) of a referral center. Seventy-five patients, 35 females (47%) were included. The mean age was 40 (±15) years. 35 patients (47%) had complex defects, and 29 patients (39%) were in NYHA class III-IV. Main symptoms were: dyspnea 22 (29 %), palpitations 20 (27%), fever 8 (11%), syncope 6 (8%), neurologic symptoms 7 (9.3%), chest pain 5 (7%). Heart failure and arrhythmias accounted for 23 (31%) and 20 (27%) of ED diagnoses. Twenty-eight patients (37%) were discharged, one patient died during observation, 32 patients (69 %) were admitted to a cardiology ward, 6 (13%) to the intensive care unit, and 8 (17%) to a non-cardiological ward. At a follow-up of 701 (554-984) days, 10 patients (13%) died, 2 (2.6%) were transplanted, 3 (4%) were listed for a heart transplant, and 30 (41 %) were re-admitted. In multivariate analysis, complex anatomy was weakly associated with readmissions. These preliminary data indicate that attendance of ACHD patients is epidemiologically relevant.