Objective To investigate the effects of blood glucose level at admission on in-hospital cardiac function in elderly acute myocardial infarction patients. Methods A total of 93 consecutive elderly patients hospitalized for first attack of acute myocardial infarction from January 2009 to August 2010 were enrolled. They were divided into 3 groups according to tertiles of the distribution of glucose level at admission: ＜7.69mmol/L (group A), 7.69-11.36mmol/L (group B), ≥11.36mmol/L(group C). The cardiac function was analyzed. Results Killip class was higher in group C than in group A and B[(2.84±1.02) vs (1.81±0.67) and (2.12±0.96), P＜0.01]. Incidence of arrhythmia was significantly higher in group B and C than in group A[(41.9% vs 35.5% and 9.7%, P＜0.05]. Ordinal logistic regression analysis demonstrated that male(OR=0.339, 95%CI 0.122-0.938, P=0.037), heart rate at admission(OR=1.034, 95%CI 1.006-1.062, P=0.018), peak CK-MB(OR=1.007, 95%CI 1.002-1.011, P=0.003) and blood glucose level at admission(OR=1.117, 95%CI 1.035-1.208, P=0.005) were independent predictors of cardiac function. Conclusion In elderly patients with acute myocardial infarction, hyperglycemia at admission is predictive of poor cardiac function.