Establishing standardized methods to assess outcome is needed to measure the effectiveness of surgery in relieving symptoms and improving quality of life. We prospectively studied 203 patients undergoing primary lumbar discectomy. Data was collected before surgery, at 3 months postoperatively and at long-term follow-up (12-60 months, median 24) using both disease-specific (visual analogue scores, Roland-Morris disability scales, and Hospital Anxiety and Depression scales) and generic (SF-36) instruments. Continued significant symptomatic benefit was observed to long-term assessment and the health gains in this patient group compared favourably with other elective surgical procedures. We have used this data to validate the SF-36 for use in this context and we recommend that SF36 should be used as a sole measure of outcome in routine practice, as well as in future studies.