OBJECTIVE: To investigate the long-term outcome of discectomy and relevant factors associated with clinical outcome. METHODS: Patients who underwent lumbar discectomy by fenestration were evaluated retrospectively, using the Oswestry disability index (ODI; 0 - 20 minimal, 21 - 40 moderate, > 41 severe disability) and the Stauffer-Coventry criteria ('excellent', 'good', 'fair', 'poor') to measure clinical and radiographic outcomes. RESULTS: Sixty patients (mean follow-up, 214 months) were included in the analysis. At final follow-up, patients were rated as 'excellent' (n = 31), 'good' (n = 13), 'fair' (n = 5) and 'poor' (n = 11) using the Stauffer-Coventry criteria; the latter group included six patients who underwent reoperations. The mean ODI score was 11.2. The height of the operative intervertebral space was significantly inversely correlated with the follow-up ODI value. Heavy manual work, smoking and a long duration of aggressive preoperative symptoms were significantly associated with unsatisfactory outcomes. CONCLUSIONS: The long-term outcome of lumbar discectomy by fenestration was satisfactory in the majority of patients. Heavy manual work, smoking and the duration of aggressive preoperative symptoms were negative predictors of a good clinical outcome.