Myoclonus is a rare neurologic complication of spinal anesthesia. We describe here a case of spinal segmental myoclonus that we encountered in a 45-year-old woman following spinal anesthesia. Spinal anesthesia was performed using 2.4 §¢ of 0.5% hyperbaric bupivacaine without any complications and surgery was uneventful. However, myoclonic movements were observed in her lower extremities 2 hours after the intrathecal injection. These movements were ameliorated by intravenous injection of diazepam. The patient fully recovered without any neurologic sequelae.