Background: Children with severe acute malnutrition (SAM) frequently present with complex comorbidities that limit the effectiveness of nutritional rehabilitation. Aim: To evaluate the association between optimization of decongestive therapy and shortterm weight change in children with CHD and SAM, and to explore its implications for nutritional assessment and surgical preparedness. Methods: This single-centre prospective observational study was conducted in a tertiary-care SAM treatment unit between 2022 and 2024. Children ≤5 years of age with WHO-defined SAM and echocardiographically confirmed CHD were enrolled. All children received standard nutritional rehabilitation. Decongestive therapy was initiated or optimized based on clinical and echocardiographic evidence of congestive cardiac failure. Weight change following clinical decongestion was recorded. Statistical analysis focused on within-subject comparisons before and after optimization of therapy . Results: Of 412 SAM admissions, 98 children (23.8%) had CHD. Among 86 children with increased pulmonary blood flow physiology , decongestive therapy was clinically indicated in 68, but only 48 were receiving any form of decongestion at admission. Following initiation or optimization of appropriate decongestive therapy , 48 of 68 children (70.0%) demonstrated a sustained weight increase of >5 g/kg/day for at least three consecutive days, while 19 showed static weight and one experienced weight loss. Paired analysis showed a statistically significant increase in postdecongestion weight (p < 0.001), with a large effect size. Conclusion: Optimization of decongestive therapy in children with CHD and SAM is associated with weight gain. Integrating early cardiac optimization into SAM management protocols may allow more accurate nutritional assessment and facilitate timely surgical referral.