Introduction: In Vietnam, knowledge about renal function in adults with congenital heart disease (CHD) is limited.Hypothesis: This study aims to estimate incidence of renal dysfunction in adults with congenital heart disease and risk factors.Methods: This is a cross-sectional study, including 365 CHD patients more than 16 years old. We collected clinical and para-clinical information, estimated glomerular filtration rate (GFR) and calculated the odds ratio (OR) for reduced GFR.Results: Totally, 52.8% patients had GFR < 90 ml/phút/1.73 m. Logistic regression had confirmed the OR for GFR < 90 ml/phút/1.73 m in the group > 60-years-old, the group with atrial fibrillation, the group with heart failure (based on NT-proBNP > 125 pmol/L), and the group with pulmonary arterial hypertension (based on pulmonary artery systolic pressure > 50 mmHg by echocardiography) were 6.46 (95% CI: 1.37 - 30.41), 7.58 (95% CI: 1.66 - 34.56), 2.98 (95% CI: 1.49 - 5.98) and 1.84 (95% CI: 1.02 - 3.33), respectively.Conclusions: Renal dysfunction is common in adults with CHD. Age > 60 years-old, atrial fibrillation, heart failure, and pulmonary arterial hypertension were risk factors for renal dysfunction in adults with CHD.