We describe 13 patients with neurological signs and symptoms associated with Mycoplasma pneumoniae infection. M. pneumoniae was isolated from the cerebrospinal fluid (CSF) of 9 patients: 5 with meningoencephalitis, 2 with meningitis, and 1 with cerebrovascular infarction. One patient had headache and difficulties with concentration and thinking for 1 month after the acute infection. M. pneumoniae was detected, by means of PCR, in the CSF of 4 patients with negative culture results. Two had epileptic seizures, 1 had blurred vision as a consequence of edema of the optic disk, and 1 had peripheral nerve neuropathy.