Objective To analyze the relationships of different blood glucose levels with medical cost, hospitalization time and disease prognosis in hospitalized patients. Methods Totally 4868 patients were checked for their blood glucose immediately after admission into hospital (not over 24 hours ) and then divided into groups: non-hyperglycemia group(3429 cases) and hyperglycemia group(1439 cases) which included the patients with diabetes or with stress hyperglycemia (patients with hyperglycemia, without diabetes history and/or with normal HbA1c level, normal glucose level during follow-up in hospital). The patients were also divided into younger group (n=2532, age＜60yrs) and older group (n=2336, age≥60 yrs). Totally 278 patients with coronary heart disease?were further divided into hyperglycemia group (120 cases) and non-hyperglycemia group (158 cases). The hospitalization time, medical cost and diseases prognosis were compared between groups. Results There were 29.5% of these patients with hyperglycemia, including 11.4% with stress hyperglycemia. Patients with hyperglycemia had significant longer hospitalization (median: 15 vs 10 d, P＜0.01), higher medical cost (median: 14064.7 vs. 8980.9 Yuan RMB, P＜0.01) and higher mortality in hospital (2.92% vs 0.61%, P＜0.01). The mortality of patients with stress hyperglycemia was significantly higher than patients without hyperglycemia, but no significant difference was found compared with patients with diabetes in younger group. There was no significant difference in the mortality between the elderly patients with diabetes and stress hyperglycemia, but were both significantly higher than patients without hyperglycemia. No statistical difference of the age was found among the diabetes, stress hyperglycemic and non-hyperglycemic patients with coronary heart disease. Patients with diabetes or hyperglycemia had significant longer hospital stay, higher medical cost and higher mortality. Conclusion The patients with admission hyperglycemia have significant higher medical cost and poor prognosis.