Electrophysiologic study including needle electromyograpy(EMG) was done in 66 patients with spina bifida who were referred to EMG laboratory. We have classified neurological impairments of spina bifida patients according to electrodiagnostic findings and the electrophysiologic study findings were compared with Magnetic Resonance Image(MRI) findings, and manual muscle test findings. Also electrophysiologic study findings were compared with urodynamic study(UDS) finding for the evaluation of neurogenic bladder in the same subjects. 55% of spina bifida patients had cauda equina lesions electrophysiologically and the most commonly involved, root was L5, and the next was S1. 42% of the subjects were normal electrophysiologically. 61% of patients with abnormal MRI findings had normal EMG findings. EMG findings did not correlated well with manual muscle tests in 44% of the subjects. Also in 44% of subjects, the electrophysiologic study was did not agree with urodynamic study findings. In conclusion, we asserts that cauda equina lesion is a most common lesion in spina bifida patients and electrophysiologic study is superior than MRI or manual muscle test in detecting neurologic deficit of spina bifida patients. However, electrophysiologic study alone offers less accurate information than urodynamic study for the evaluation of neurogenic bladder in spina bifida patients.