Background <p>Transposition of the great arteries is a critical congenital heart defect characterized by the reversal of the aorta and pulmonary arteries, resulting in two parallel circulatory pathways. This condition is typically incompatible with life unless a shunt, such as an atrial or ventricular septal defect, facilitates the adequate mixing of oxygenated and deoxygenated blood in the heart. Survival into adulthood without surgical correction is exceptionally rare. While a limited number of cases have been reported globally, none, to the best of our extensive search, have been associated with a patent ductus arteriosus and pulmonary artery aneurysm.</p> Case presentation <p>We present a unique case of a 25-year-old Ethiopian male with complex dextrotransposition of the great arteries, who survived into adulthood and presented with acute decompensated heart failure. Remarkably, this patient had a constellation of associated anomalies, including an atrial septal defect, ventricular septal defect, patent ductus arteriosus, and severe pulmonary hypertension. Owing to resource limitations, insufficient medical knowledge, and financial constraints, the patient was managed conservatively. Despite these challenges, the patient showed symptomatic improvement with the conservative management provided.</p> Conclusion <p>This case offers novel insights into the natural history of untreated dextrotransposition of the great arteries with multiple associated anomalies in adults. It also underscores the challenges of managing complex congenital heart defects in resource-limited settings and highlights the urgent need for accessible advanced diagnostic and therapeutic interventions to improve outcomes for similar patients.</p>