This discourse is aimed at elucidating prognostic criteria for the assessment of the course of a paresis in the case of lumbar disc herniation. Fourhundred and fifty patients were examined who had been operated on for lumbar disc herniation at the Orthopaedic University Clinic Mainz between 1986 and 1991. Of these, 240 showed radicular paralytic symptoms. They were examined prior to the operation, immediately afterwards and 1 year after the operation. The influence of the degree of intensity of the paresis, the time elapsed since the occurrence and other factors like nerve root affected, intraoperative findings, age, sex and weight of the patient were registered. It is obvious that the degree of intensity of a paresis is a good prognostic criterion for the assessment of the postoperative course. A paresis classified as grade III or IV receded in more than 70% of the cases within 6 months. For a paresis of grade II, the recovery rate was 40%. In the case of a total paresis, no complete neurological recovery was registered. The period of time which had elapsed since the occurrence of the paresis, the weight of the patient, the nerve root affected and other factors did not show any significant influence. As a criterion for an emergency or postponed operation on a herniated disc, the duration of paralytic symptoms should therefore be attributed less importance than the progression.