This study aimed to evaluate the association between serum galectin levels and renal dysfunction in relation to in-hospital prognosis and unfavorable prognosis 1 year after ST-elevated myocardial infarction (STEMI). Patients were assigned to two groups according to the cystatin C-based estimate of GFR on day 12 after STEMI: (1) STEMI patients with normal renal function (GFR based on cystatin C levels = 60 mL/min/1.73 m(2)) and (2) those with renal dysfunction (RD) (GFR based on cystatin C levels <60 mL/min/1.73 m(2)). A decrease in GFR estimated from the CKD-EPI equation on day 12 was more frequently found in patients with a reduced GFR based on cystatin C levels (41.9%) compared with those without RD (21.3%). Galectin levels exceeded the cut-off value (17.8 ng/mL) in 50.6% of cases in the group with GFR <60 mL/min/1.73 m(2) and in 32% of cases in the group with a normal GFR. The presence of RD and elevated galectin levels >17.8 ng/mL on day 12 after MI are independent predictors of an adverse prognosis at 1 year in STEMI patients. Elevated galectin levels are directly correlated with the presence of early postinfarction angina.