We describe 17 patients with acquired convergence-evoked nystagmus (CEN). Vertical CEN was most common (82%), with upbeat much more frequent than downbeat. The most common diagnoses were multiple sclerosis (41%) and brainstem infarction (29%). CEN is an easily elicited bedside sign of posterior fossa dysfunction and can be a clinically useful manifestation. In cases of isolated optic neuritis, the presence of CEN may indicate dissemination of neurologic disease.