Fasting hyperglycemia is associated with poor neurologic outcome in acute ischemic stroke (AIS), but its relationship with in-hospital outcome in elderly patients remains largely unknown. To assess the association of in-hospital outcome with fasting plasma glucose (FPG) levels at admission in individuals with AIS. This retrospective propensity score-matched case-control study included patients aged over 60 years suffering from AIS and who were admitted to the emergency department from November 2013 to October 2016. Subjects were grouped into the poor-outcome and good-outcome groups based on mortality and intensive care unit (ICU) admission. The poor- and good-outcome groups comprised 74 and 1927 cases, respectively, before propensity score matching (PSM), and 74 and 296 cases, respectively, after PSM. Univariable logistic regression analysis showed that initial FPG after admission was associated with poor in-hospital outcome. Multivariable logistic regression analysis showed that initial FPG after admission was an independent predictor of poor in-hospital outcome (odds ratio=1.11, 95% confidence interval: 1.037-1.188, P=.003). This study used PSM and strongly suggests that FPG is an independent predictive factor of poor in-hospital outcome in elderly patients with AIS. High initial FPG levels after admission may predict poor in-hospital outcome. Prospective studies are needed to confirm these findings.