A 341 patients with lumbar disc herniation were operated for a period of 9 years (1997-2005) in the Neurosurgical clinic of Varna. On the postoperative follow-ups 45 of them presented with unsatisfying results. The main factors caused recurrent low back pain were spinal stenosis (central or lateral), residual disc fragments, epidural fibrosis, disc herniation on another level, spinal nerve root damage, infections, psychological or other unknown factors. The results were estimated for a short- and long-term period. Scripta Scientifica Medica 2007; 39(2):187-189