Canavan's disease is a hereditary disease that causes development delay by demyelinization of white matter in brain. The cardinal symptoms of Canavan's disease are head-lag, macrocephaly, developmental delay, blindness, epilepsy and hypotonia. Seven-month old baby delivered by Caesarean section at gestational age 40 weeks was complaining of an inability to keep head up. In past history, he was treated for congenital nystagmus. Chromosomal study was normal. Brain MRI showed delay of myelination of 5 months old. During neurodevelopment treatment in our hospital about development delay, macrocephaly was observed with head circumference 46 cm (90~97 percentile). He couldn't control his head yet. Brain MRI was done when he was 12-month old. There was no myelination in whole brain compared with that of same age group. The peak elevation of N-acetylaspartic acid (NAA) was showed in magnetic resonance spectroscopy (MRS). NAA was detected as high as 29.7 mmol/molCr, we diagnosed him as Canavan's disease. So we reported this case with a brief review of related literatures.