For the purpose of ascertaining the role and magnitude of ischemia of the spin-al cord following trauma the authors determine the lactate concentrations in cere-brospinal fluid(CSF). Laminectomies were performed at L2 under general anes-thesia with aseptic techniques. Paraplegia was produced by 400 gm-cm impact injury with impounder. Significant increases in CSF lactate levels occurring at Day 5. The prolonged elevation of CSF lactate indicates that tissue hypoxia plays a role in spinal cord damage and that there is a continuing hypoxia of metabolically active spinal cord tissue for several days post injury.