To prevent recurrence and avoid the second operation, the authors analyzed the clinical features and surgical outcome of 214 patients (157 males and 57 females) who underwent lumbar microdiscectomy, 16 of whom required second operation. The mean age was 34,6 years (range, 12–62 years). The average Follow-up period was 4 years 5 months. The overall incidence of second operation was 7.5%. Second operation was performed because of recurrence of herniation in nine patients, and residual bony compression at the lateral recess in two, The incidence of second operation was significantly higher in teenagers than in patients in other age decades (P > 0.01), and In patients with protrusion-type hernietion than in those with extrusion-type or sequestretion-type hemiation (P > 0.01). To prevent the necessity for second operation, careful and thorough discectomy, especially deep to the posterior longitudinal ligament, and decompression at the lateral recess are useful.