['Hyperglycemia on admission is associated with increased mortality rates in patients with ST-elevation myocardial infarction (STEMI) who are treated with either fibrinolytic therapy (FT) or primary percutaneous coronary intervention (PCI). However, data regarding the relationship between hyperglycemia and the success of FT are lacking. The aim of this study was to investigate the value of admission blood glucose for the prediction of failed reperfusion following FT.', 'This is a retrospective study of 304 STEMI patients who received FT and whose admission glucose levels were recorded. The main outcome measure was ST segment resolution≥50%. The median (interquartile range [IQR]) blood glucose level in the entire study group was 112 (95-153). In 92 (30.2%) patients, FT was unsuccessful and rescue PCI was performed. Admission glucose (126 [99-192] vs. 110 [94-144] mg/dL, p<0.001), time from symptom onset to FT (180 [120-270] vs. 150 [120-180] min, p=0.009), and maximum ST elevation amplitude (3 [2-7] vs. 3 [2-6] mm, p=0.05) were higher in the failed reperfusion group than in the reperfusion group. Admission hyperglycemia was an independent predictive factor for failed reperfusion (hazard ratio 4.79 [1.80-12.76], p=0.002), along with time from symptom onset to fibrinolysis and anterior wall myocardial infarction.'] Is admission hyperglycemia associated with failed reperfusion following fibrinolytic therapy in patients with STEMI : results of a retrospective study?