Neuromyotonia, or Isaacs' syndrome, consists of continuous muscle fiber activity caused by hyperexcitability of the peripheral nerves. Rarely, these patients also develop CNS symptoms characterized by confusion, insomnia, hallucinations, and agitation. A rare disease consisting of neuromyotonia, autonomic symptoms, and CNS dysfunction is called Morvan's syndrome. We report a 24-year-old man who presented with insomnia, malaise, anorexia, hyperhidrosis, palpitation and myokymia in both the lower extremities. The pathomechanism of Morvan's syndrome is related to the voltage-gated K+ channel (VGKC) antibodies.