Opsoclonus-myoclonus-ataxia syndrome (OMAS) is an autoimmune disorder involving the nervous system characterized by rapid involuntary eye movements (opsoclonus), involuntary brief muscle twitching (myoclonus), loss of coordination of movements, imbalance, disturbances of sleep, irritability, slurring of speech, and decreases muscle tone. Hyperemesis gravidarum, intractable vomiting during pregnancy, results in reduction in intravascular volume, can produce ketonemia. We describe a case of primigravida who had hyperemesis gravidarum and suffered metoclopramide-induced OMAS.