This study is an attempt to assess the possible effect of ACE Insertion/Deletion polymorphism on response to steroid in Egyptian children with idiopathic nephrotic syndrome.To achieve this goal 53 patients diagnosed as idiopathic nephritic syndrome were studied. Median age at onset of the disease was 4 years (range, 1.5–13.0), visiting nephrology clinic, Pediatric Hospital of Cairo University with regular follow up period for minimum of 6 months, including 36 males (67.9%) and 17 females (32.1%). All patients received in the initial episode of nephrotic syndrome prednisolone in a dosage of 2 mg/kg/day in 3 divided doses for 4 weeks(6 weeks in the case of steroid non responsiveness), followed by a single 2 mg/kg dosage in the morning of every other day for 4 weeks. After that the alternate-day treatment continued but the dosage was reduced by 12.5% every 2 weeks for the following 3-4 months.