Stress hyperglycemia is commonly identified in children with severe illness and previously normal glucose homeostasis. In the pediatric population febrile seizures are reported among stress-related conditions associated with stress hyperglycemia. The objective of this prospective study was to evaluate the possible association between blood glucose level and febrile seizure severity defined by fever degree, seizure type, seizure duration and hospitalization length. Among 167 febrile seizures the prevalence of stress hyperglycemia (blood glucose concentration over 150mg/dl) was 13.22%. There was a highly significant statistical association between seizure duration (exceeding 15 minutes) and increased blood glucose concentration (p= 0.001). Prolonged febrile seizures combined with high fever were significant risk factors for stress hyperglycemia. Further analysis on acute fluctuation of glycemia, persistence of hyperglycemia should be taken in consideration as possible predictive factor for stress hyperglycemia, by comparison to the peak blood glucose concentration