ABSTRACT BACKGROUND፡ Children with Congenital Heart Disease (CHD) are at increased risk for severe acute malnutrition (SAM). We aimed to determine the magnitude and determinants of SAM among children with CHD in a tertiary hospital.METHODS: Retrospective cross-sectional study was conducted among children with CHD between 2016 and 2019. Clinical and anthropometric data were retrieved from medical records. Anthropometric assessment was done by using WHO standard growth curves.  Data analysis was done using Statistical Package for Social Sciences V22. Statistical significance was set at p-value <0.05, and multivariable logistic regression was used to determine predictors.RESULTS: There were 2400 pediatric admissions during the study period,CHD accounted for 6.5%(156) of admissions. For review, 141 records were eligible. The gender distribution was comparable, males 51.1% (72). Infants (<12 months) and older children (>12 months) accounted for 57.4% (81) and 42.6% (60) of study subjects, respectively. SAM was documented in 51.8% (73) of the study subjects, [95% CI: 44.7-60.2]. Infants had higher odds of SAM compared to children aged >12 months[adjusted odds ratio (AOR)= 4.48, 95%CI:2.07-9.70]. Anemic children had higher odds for SAM[AOR =3.76, 95% CI:1.54-9.18]. Children without acyanotic CHD with heart failure(HF) were 58% less likely to develop SAM[AOR= 0.42, 95% CI:0.19-0.96].CONCLUSION: The burden of SAM among children with CHD is high. Younger age,anemia and acyanotic CHD with HF predicted SAM.Screening for anemia and targeted anthropometric assessment are recommended for early SAM detection.KEYWORDS: Congenital heart disease, severe acute malnutrition, Ethiopia