Malnutrition is a prevalent and clinically significant complication in infants with congenital heart disease (CHD), particularly when associated with chronic heart failure (CHF). Nutritional deficits contribute to delayed growth, impaired immune function, and adverse surgical outcomes.Objective: To evaluate the clinical effectiveness of a structured enteral nutritional intervention in improving nutritional status among infants with CHD and CHF.Methods: A prospective, single-center study enrolled 18 infants (1–12 months) with CHD and CHF. Nutritional status was assessed using anthropometric measurements, biochemical markers, and the STRONGkids screening tool. Individualized target enteral nutrition was provided for 14 days. Paired comparisons were conducted to determine changes in nutritional and biochemical parameters.Results: At baseline, 74% of participants exhibited moderate or severe malnutrition. After 14 days of nutrition intervention, mean body weight increased by 10.3% (p < 0.05), mid-upper arm circumference and skinfold thickness improved significantly, and serum albumin and prealbumin levels rose (p < 0.05). The proportion of infants classified as high nutritional risk decreased from 100% to 11.1%.Conclusion: Early, targeted enteral nutrition yields significant improvements in anthropometric and biochemical indicators of nutritional status in infants with CHD and CHF. Integration of systematic nutritional support into pediatric cardiology care is recommended to optimize clinical outcomes.