Glioblastomas are among the most common primary brain tumors with an abysmal prognosis. The significance of glucose metabolism in glioblastoma cell metabolism and proliferation is well-known. However, a significant correlation between the systemic metabolic status of the patient and the cellular proliferation of the glioblastoma has not yet been established. Our aim was to observe and analyze for a possible correlation between glioblastoma cellular proliferation and patients' glycated hemoglobin (HbA1c) levels as a marker of chronic systemic glycemia. We analyzed the data from 25 patients and compared their Ki-67 values with their preoperative HbA1c values. We observed a statistically significant correlation (P < 0.03) between chronic glycemia (measured using HbA1c) and the cellular proliferation of glioblastoma (measured by cellular Ki-67 expression). These results imply a possible positive correlation between glioblastoma cell proliferation and chronic systemic glycemia, a correlation that, to the best of our knowledge, has not yet been reported. Further research in this area could not only lead to a better understanding of glioblastoma but also have significant clinical applications in treating this devastating disease.