The aim of this study was to evaluate the efficacy of a low glycemic index diet on seizure frequency, oxidative stress markers and quality of life in children with drug-resistant epilepsy.This study was a prospective, non-randomized, single centre intervention conducted in children with drug-resistant epilepsy. Low glycemic index diet was started on an out-patient basis. Children and their parents were educated about the diet and the effect of the diet on seizures. Children who were willing to follow the diet were included in the study. The research dietitian conducted interviews with patients and their parents at the beginning of the study to explain the principles of the diet.At baseline and at outpatient clinic follow-ups at 3 months, anthropometric measurements were taken, the strengths and difficulties questionnaire (SDQ), Pediatric Inventory of Quality of Life (PedsQL) and depression scales were administered and samples for biochemical measurements including oxidative stress parameters were collected. A 3-day dietary intake chart kept by the parents was reviewed at each monthly visit to check and reinforce compliance. Parents were asked to record the seizure frequency and severity in a seizure diary.