Despite adequate surgery, a number of patients have a return of back pain and radiculopathy of the legs following their operation. We present here a case of spinal myoclonus with radiculopathy after spine surgery. A 51 year old woman with bilateral radiculopathy and urinary incontinence was diagnosed with a cauda equina syndrome along with spinal stenosis. The patient underwent emergency operation for posterior decompression and internal fixation from the L2 to S1 levels. Immediately after surgery, the patient continued to experience intermittent myoclonic movement with severe shooting pain in her legs despite being given pharmacological treatments such as benzodiazepines, opioids, NSAIDs and gabapentin. The patient was found to have sudden, brief, bilateral involuntary muscle contraction on the lower extremities. The patient was referred to our pain clinic. She underwent a caudal block 2 times in 4 days. However, she reported only limited pain relief for 3 to 4 hours. She was then prescribed phenytoin 300 mg intravenously in a day; her myoclonic movement gradually subsided after 1 week of receiving phenytoin. Sixty days later, she was discharged without any long term sequelae.