Two hundred eighty patients with herniated lumbar discs, verified by radiculography, were divided into three groups. One group, which mainly will be dealt with in this paper, consisted of 126 patients with uncertain indication for surgical treatment, who had their therapy decided by randomization which permitted comparison between the results of surgical and conservative treatment. Another group comprising 67 patients had symptoms and signs that beyond doubt, required surgical therapy. The third group of 87 patients was treated conservatively because there was no indication for operative intervention. Follow-up examinations in the first group were performed after one, four, and ten years. The controlled trial showed a statistically significant better result in the surgically treated group at the one-year follow-up examination. After four years the operated patients still showed better results, but the difference was no longer statistically significant. Only minor changes took place during the last six years of observation.