© 2022 Turkish Society of Cardiology. All rights reserved.Objective: Galectin-3 is a biomarker used to detect cardiac remodelling and fibrosis. It could also potentially be a biomarker for developing new treatments. Aldosterone and galectin-3 levels and their relationship to N-terminal pro-brain natriuretic peptide (NT-proBNP) and left ventricular dilatation have not yet been studied in infants with ventricular septal defect (VSD). In this study, we aimed to investigate the biomarker feature of galectin-3 in infants with VSD. Methods: Aldosterone, galectin-3, and NT-ProBNP levels were quantified and left ventricular diameters were measured with M mode echocardiography in infants with isolated VSD who had received heart failure treatment. The results were compared with those of healthy children of similar age and gender. Results: This study included 22 infants (13 girls, nine boys) with VSD who formed the patient group and 22 healthy infants (13 girls, nine boys) who formed the control group. There was a significant difference between the two groups regarding the median left ventricular end-diastolic diameter and the median left ventricular end-systole diameter. The patient and control groups had no significant difference with respect to aldosterone levels (median values 43.5 pg/mL vs 41.3 pg/mL, respectively) (P = .851), although there was a significant difference with regard to galectin-3 levels (median values: 4 vs 2.5 ng/mL, respectively) (P = .015) and NT-proBNP levels (median values: 204.3 vs 94.2 pg/mL, respectively) (P = .003). Conclusion: Galectin-3 increases independent of left ventricular dilatation and may have a biomarker value with similar strength as NT-proBNP in infants with VSD.