In patients with the trisomy 13 syndrome the most commonly encountered brain anomaly is holoprosencephaly, which occurs in approximately 80% of cases. In trisomy 13 patients without holoprosencephaly, previously reported anomalies include callosal dysgenesis, hippocampal hypoplasia, olfactory hypoplasia, and cerebellar dysplastic changes such as vermian hypoplasia and dysplastic cortices. Dysplasia of the cerebral cortex, however, has not been reported before. We describe a newborn with bilateral, dysplastic cortices at the perisylvian and rolandic regions. These dysplastic cortices probably accounted for the clinical findings of seizures, oromotor dysfunction, dystonia flexion contractures in the hands, which were consistent with a recently described syndrome labelled as the "congenital bilateral perisylvian syndrome".