In a prospective study 122 patients with a slipped lumbar disc and no previous surgery were preoperalively examined for fibrinolytie activity. Surgical results for these patients were evaluated 12 months postoperatively by clinical overall assessment. In a multiple linear regression analysis fibrinolytic variables, euglobulia clot lysis time and plasminogen activator inhibitor 1, were shown to have predictive value regarding outcome of surgery; that is, normal fibrinolytic activity favors a satisfactory outcome and vice versa. Background variables and lipid profile were also recorded preoperatively. Body mass index, P-glutamyl transpeptidase, triglycerides and smoking were of statistical significance in relation to euglobulin clot lysis time and plasminogen activator inhibitor 1. Postoperative fibrinolytic re-examination of 20 patients seem to contirm that patients at risk of surgical failure have a prolonged depression of fibrinolytic activity.