A case that was diagnosed prenatally as having open spina bifida by ma
gnetic resonance imaging (MRI) and ultrasound (US) examination is repo
rted. At the time of the third US examination, the spina bifida cystic
a was detected, but it could not be determined by US whether it was op
en or closed spina bifida. A lumbosacral skin defect was detected on M
RI, which permitted prenatal diagnosis of open spina bifida. Surgical
repair was performed immediately after delivery. Prenatal intrauterine
evaluation of the fetal CNS morphology and malformation has advanced
with the improvement of diagnostic tools. Each diagnostic tool, howeve
r, has its own advantages and disadvantages. In prenatal intrauterine
evaluation, it is important that observation be made through the combi
ned use of multiple diagnostic tools.