INTRODUCTION: Stress HYPERGLYCEMIA is defined as a transient increase in blood glucose concentration during an acute physiologic stress. The study was done to demonstrate the relative frequency of stress HYPERGLYCEMIA in children admitted to AL-Zahra hospital emergency department from March 1998 to December 1998.MATERIAL & METHODS: This study was cross-sectional descriptive and included 291 patients (6 months to 5 years old), all required venipuncture, who were selected by simple sampling method. Blood glucose ≥ 200 mg/dl was considered as HYPERGLYCEMIA and any clinical, diagnostic and surgical procedure that led to hospitalization of the baby was defined as stress . RESULTS: The relative frequency of HYPERGLYCEMIA, normoglycemia and hypoglycemia were 25.42%, 72.18% and 2.40% respectively. There was not any significant difference between boys and girls (P>0.05) in this regard. 130 subjects were encountered with one kind of stress and the relative frequency of HYPERGLYCEMIA was different base on the kind of stress (50% in hematologic diseases, 40% in respiratory diseases and 29.4% in gastrointestinal diseases). Relative frequency of stress HYPERGLYCEMIA among patients with 2 or more stresses was 24.22% which was not significantly different from those with one stress (P>0.05). CONCLUSION: It seems that HYPERGLYCEMIA stress is not related to the number of stresses of patients but is associated with the type of the disease.Relative frequency of HYPERGLYCEMIA stress in this study (25.42%) was differ from those reported by others (51.9% in ICU inpatients and 0.46% to 9.4% in other departments) which may be attributed to the addmission of intensive care service needed patients with other patients in emergency department in AL-Zahra hospital.