Foot drop is a common and debilitating finding in patients with lumbar spinal disorders. Recovery of function after surgical treatment of the underlying disorder is not well documented in the literature. The purpose of this retrospective study was to analyze the prognosis of preoperative foot drop after lumbar surgery in 55 patients with foot drop and herniated nucleus pulposus and/or lumbar spinal stenosis. Preoperative dorsiflexion motor strength improved measurably in 98%, and 71% had full recovery of strength. All patients had associated neurologic findings and 71% experienced complete resolution. No statistically significant relationship was found between the extent of recovery and age, diagnosis (herniated nucleus pulposus lumbar spinal stenosis), duration of symptoms, or severity of preoperative weakness. In our series, the prognosis of preoperative foot drop and associated neurologic deficits treated by lumbar spine surgery was excellent.