<jats:sec> <jats:title>Background—</jats:title> <jats:p>Galectin-3 is a biomarker associated with inflammation and fibrosis that predicts adverse outcome and relates to biomarkers of extracellular matrix turnover in patients with heart failure, particularly when left ventricular (LV) systolic function is preserved. Whether galectin-3 is related to LV remodeling after acute myocardial infarction is unknown.</jats:p> </jats:sec> <jats:sec> <jats:title>Methods and Results—</jats:title> <jats:p> Circulating galectin-3 and various extracellular matrix biomarkers were measured in 100 patients (age, 58.9±12.0 years; 77% men) admitted with acute myocardial infarction and LV dysfunction, at baseline (mean 46 hours) and at 24 weeks, with cardiac MRI at each time-point. LV remodeling was defined as change in LV end-systolic volume index. Relationships among galectin-3, biomarkers, and LV remodeling were analyzed across the entire cohort, then according to median baseline LV ejection fraction. Galectin-3 levels were elevated in 22 patients (22%) at baseline and increased significantly over time from 14.7±5.5 to 16.3±6.6 ng/mL ( <jats:italic>P</jats:italic> =0.007). Baseline galectin-3 did not correlate with any LV parameters at baseline or change in any parameter over time. Galectin-3 was positively associated with remodeling in patients with supramedian baseline LV ejection fraction (ie, >49.2%; <jats:italic>r</jats:italic> =0.40; <jats:italic>P</jats:italic> =0.01) but not when LV ejection fraction was ≤49.2%. Galectin-3 correlated significantly with matrix metalloproteinase-3 and monocyte chemoattractant protein-1 at baseline, biomarkers that have been shown to relate to LV remodeling in this cohort. </jats:p> </jats:sec> <jats:sec> <jats:title>Conclusions—</jats:title> <jats:p>Galectin-3 correlated significantly with certain biomarkers involved in extracellular matrix turnover, although no definite relationship was identified with LV remodeling. Whether galectin-3 plays a pathological role in remodeling remains unclear but merits further study.</jats:p> </jats:sec> <jats:sec> <jats:title>Clinical Trial Registration—</jats:title> <jats:p> URL: <jats:ext-link xmlns:xlink="http://www.w3.org/1999/xlink" ext-link-type="uri" xlink:href="http://www.clinicaltrials.gov">http://www.clinicaltrials.gov</jats:ext-link> . Unique identifier: NCT00132093. </jats:p> </jats:sec>