We performed a retrospective review of all the infants diagnosed with trisomy 13 in our institution from 1982 to 1995 and evaluated the neurosonographic findings along with their clinical information and cytogenetic analysis. Nine babies were admitted with trisomy 13. Sonography of the head was performed on 4 patients, and demonstrated in all of them a linear, branching, echogenic pattern in the thalamus/basal ganglia. Doppler evaluation of the thalamus/basal ganglia was performed in 3 of the 4 cases and confirmed these linear echogenicities to be of vascular origin. This is the first study to evaluated the occurrence of this finding in a specific syndrome, namely trisomy 13.