The growing population of adults with congenital heart disease (ACHD) highlights the urgent need for specialized care. Most congenital heart surgeries are palliative rather than curative, resulting in residual lesions, complications such as heart failure and arrhythmias, and non-cardiac issues requiring lifelong management. Unique pathophysiological features, such as systemic right ventricle and Fontan circulation, differentiate ACHD from acquired cardiovascular diseases, posing challenges in applying existing evidence-based treatments. Heart failure is a leading cause of mortality in ACHD, necessitating tailored management strategies, including emerging pharmacological treatments like ARNI and SGLT-2 inhibitors, as well as non-pharmacological options like cardiac resynchronization therapy and heart transplantation. Arrhythmias, including atrial tachycardia and ventricular arrhythmias, are major causes of morbidity and mortality, emphasizing the importance of timely evaluation and intervention, such as catheter ablation. Surgical management demands precise risk assessment and a multidisciplinary team approach. End-of-life care is particularly complex, as ACHD patients often struggle with disease awareness and decision-making due to lifelong medical dependence. Collaboration among specialists, including cardiologists, pediatricians, and palliative care providers, is essential to address these challenges.