An 8-year-old boy with symptomatic late-onset congenital syphilis is reported. The child had been undertreated when he was 78 days of age, but his clinical and serologic follow-up did not occur until he was 3 years of age. At that time, he was asymptomatic, and cerebrospinal fluid disclosed not only hypercellularity but also a reactive Venereal Disease Research Laboratories test. Although he was then retreated at 4 years of age, he developed seizures. Cranial computed tomography and magnetic resonance imaging were normal, but two single photon emission computed tomography scans performed when he was 5 years of age and then 7 years of age demonstrated areas of hypoperfusion that closely agreed with the alterations on electroencephalograph. Brain single photon emission computed tomography was able to detect cerebral nervous system abnormalities in this young patient with neurosyphilis, whereas other image studies did not.