Selective lumbosacral radiculography and block was performed on 106 patients, using 60% Conray or Dimer-X and 1% lidocaine mixed with corticosteroid. The technique of this method is reported, and the radiculographic findings and diagnostic value of this method are discussed. According to our experience, this method is technically simple and very useful in determining the limit of the lumbosacral nerve root lesion, and occasionally can be used to relieve radicular symptoms. We think it is an especially excellent diagnostic technique for disorders featuring nerve root entrapment in the lateral foraminal recess, in which accurate localization cannot be determined by the other auxiliary diagnostic measures.