Background: Glucose-6-phosphate dehydrogenase (G6PD) deficiency is one of the most known enzyme defects in Iran with various genetic mutations. We aimed to study the predisposing factors of hemolysis in children with G6PD deficiency.
Methods: This study was done during 2007-2012 in two referral centers of Mofid Children’s Hospital and Baqiyatallah Hospital, Tehran, Iran. The hospital records of the patients were fully reviewed and questionnaires for each patient were filled for the date of admission, initial symptoms, initial laboratory results, family history and history of any drug consumption, infection or fava bean ingestion. 
Results: Medical records of 192 children with mean age of 4.2 years (1 month to 14 years) were extracted. 68.2% of the cases were male. Hemolytic crises were significantly more common in spring which is the peak time for fava bean consumption and occurred more frequently in those with a family history of G6PD deficiency especially in females. The most common initial symptoms were jaundice (71%), dark color urine (49%), fever (34.4%), and pallor (24.5%), followed by abdominal pain (16.7%). Fava bean intake (93%) was the first etiological agent triggering hemolysis followed by infectious agents and drug consumption. Initial hemoglobin level was significantly lower in male patients.
Conclusion: Regarding the high prevalence of G6PD deficiency in Iran, we should emphasize on education of parents and physicians about the disease and prevention of fava bean ingestion in people with G6PD deficiency.