Background: Diarrhea is a leading cause of illness and death in children of developing countries, where an estimated 1300 million episodes and 3.2 million deaths occur in under-5 children. About 80% of deaths due to diarrhea occur in the first 2 years of life. Convulsions may occur during a diarrheic illness. Children may develop febrile seizures if fever accompanies the diarrhea. Objective: The aim of the current work was to investigate the prevalence and determinant risk factors of seizure in children with gastroenteritis in children admitted to Aswan University Hospital in Egypt. Patients and Methods: This prospective cross-sectional study included a total of 60 children having gastroenteritis and seizure, attending at Aswan University Hospital. This study was conducted between April 2019 to the end of September 2019. Results: 46.7% of cases had mild fever, 61.7% of cases had gastroenteritis >5 days, vomiting frequency was > 3 times per day in 73%. Mean serum calcium was 5.55 ± 0.614 mg/dl, mean potassium was 4.72 ± 0.632mmol/L, mean sodium was 135.67 ±5.82 mmol/L and mean PH was 7.36 ±0.694. Acidosis and hyponatremia were the most frequent disorder among the patients. High grade fever, gastroenteritis >5 days and vomiting more than 3 times per day were significantly more frequent in patients with convulsion compared to non-convulsion patients. Conclusion: Electrolyte impairment is fairly common in children with acute gastroenteritis. High grade fever, gastroenteritis for > 5 days, vomiting >3 times per day, blood urea nitrogen, potassium and sodium found to be significant predictors of convulsion.