The use of closed suction drainage after spinal surgery remains controversial. The purpose of this study was to determine the indications for closed suction drainage after single-level lumbar surgery. Two hundred patients who were scheduled to undergo single-level lumbar surgery without fusion were prospectively randomized into two groups. One group had a closed wound suction drain placed deep to the lumbodorsal fascia before routine closure, whereas the second group had no drain placed. Hemostasis was achieved in all patients before the surgeon had knowledge of the randomization outcome. All drains were removed on the 2nd postoperative day, and the amount of drainage was recorded. After surgery, the patients were evaluated for signs and symptoms of continued wound drainage, hematoma/seroma formation, and/or infection as well as evidence of an acquired neurologic deficit. One hundred three patients had a drain placed before closure and two patients developed postoperative wound infection, both of which were successfully treated with orally administered antibiotics. Of the 97 patients who had no drain placed after the surgical procedure, one patient developed a postoperative wound infection that was treated with surgical incision and drainage, as well as intravenously administered antibiotics. Statistical analysis revealed that the presence or absence of a drain did not affect the postoperative infection rate. No new neurologic deficits occurred in any postoperative patient. The use of drains in single-level lumbar laminectomy without fusion did not affect patient outcome. There was no significant difference in the rate of infection or wound healing and no patient developed a postoperative neurologic deficit.